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Nevets
Sep 11, 2002

Be they sad or be they well,
I'll make their lives a hell
The fact that the conduit doesn't end in a right angle poking straight up and then enter the garage 1 foot above grade like mine does is a big win for you.

Edit: Wait, somebody ran 2 separate 20amp circuits underground to a detached garage instead of 1 service line and a new subpanel and it was only 3 years ago? I assumed it was some 1980's wild west hackjob.

Nevets fucked around with this message at 22:15 on Oct 11, 2018

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TooMuchAbstraction
Oct 14, 2012

I spent four years making
Waves of Steel
Hell yes I'm going to turn my avatar into an ad for it.
Fun Shoe
Gotta save that $100 on a panel and a couple of circuit breakers.

Jealous Cow
Apr 4, 2002

by Fluffdaddy

Nevets posted:

The fact that the conduit doesn't end in a right angle poking straight up and then enter the garage 1 foot above grade like mine does is a big win for you.

Edit: Wait, somebody ran 2 separate 20amp circuits underground to a detached garage instead of 1 service line and a new subpanel and it was only 3 years ago? I assumed it was some 1980's wild west hackjob.

Yes, and it's a shame because I didn't really realize how stupid it was when they were doing the work. It's a 4000qsft 1914 house and I had the the electrical completely redone in 2015. There was just too much other stuff going on.

kid sinister
Nov 16, 2002

Jealous Cow posted:

Yes, and it's a shame because I didn't really realize how stupid it was when they were doing the work. It's a 4000qsft 1914 house and I had the the electrical completely redone in 2015. There was just too much other stuff going on.

Dang. If you went to that extent for your whole place only 3 years ago, I'm surprised that your electrician didn't try to upsell you for a big garage subpanel to run your electric car chargers, welders, workshop, etc.

Also, that is a friggin giant 100 year old house. Is it all that old or were there some additions?

kid sinister fucked around with this message at 22:28 on Oct 11, 2018

Jealous Cow
Apr 4, 2002

by Fluffdaddy

kid sinister posted:

Dang. If you went to that extent for your whole place only 3 years ago, I'm surprised that your electrician didn't try to upsell you for a big garage subpanel to run your electric car chargers, welders, workshop, etc.

Also, that is a friggin giant 100 year old house. Is it all that old or were there some additions?

it used to have a screened in porch that ran along the living room with two French doors to access it. That was enclosed in the 40s and turned into two additional rooms, plus a walk in closet and bathroom. Total dimensions of the additional are about 42x15.

The main two levels are about 3400sqft. Attic is another 700ish finished, basement is about 1300sqft with 8 foot ceilings but isn’t totally finished.

It’s got all new plumbing, dual zone HVAC, new kitchen, new bathrooms, but the original layout and finishes. Mostly plaster, original hardwood. It’s amazing and I love it. It’s my colonial loving mansion on .75 acres 3 miles from downtown Cleveland.

Here’s the rest of the sub panel, the main, and my handling live wires trying to figure out the gauge.







Edit:

Here’s where it comes into the garage



And here’s the inside of the box in the garage where it comes in



I have an electrician coming out next Tuesday. I’ll update y’all then.

Jealous Cow posted:

it used to have a screened in porch that ran along the living room with two French doors to access it. That was enclosed in the 40s and turned into two additional rooms, plus a walk in closet and bathroom. Total dimensions of the additional are about 42x15.

The main two levels are about 3400sqft. Attic is another 700ish finished, basement is about 1300sqft with 8 foot ceilings but isn’t totally finished.

It’s got all new plumbing, dual zone HVAC, new kitchen, new bathrooms, but the original layout and finishes. Mostly plaster, original hardwood. It’s amazing and I love it. It’s my colonial loving mansion on .75 acres 3 miles from downtown Cleveland.

Here’s the rest of the sub panel, the main, and my handling live wires trying to figure out the gauge.







Edit:

Here’s where it comes into the garage



And here’s the inside of the box in the garage where it comes in



I have an electrician coming out next Tuesday. I’ll update y’all then.

Had an electrician stop by this morning.

He offered me these options:

1) reuse the existing wires, but he could only give me 20A/240v.

2) Pull new wires using the existing ones, but he said there’s a risk of losing a wire and the max he could do is 40A/240v.

3) Run an overhead line from the house to the garage for a new panel. Up to 100A.

I really don’t want to run an overhead wire, but there’s already coax and fiber running overhead from the garage to the house since the pole with those services is behind the garage, so what’s one more I guess.

Jealous Cow fucked around with this message at 17:21 on Oct 14, 2018

H110Hawk
Dec 28, 2006

Blackbeer posted:

You could put a 2x4 (flat against the outer wall) in the side stud space below the panel and nail to that if there's room. Sometime's I'll nail a staple to a stud and then fasten several wires to it with a nylon zip tie. If you have more than 6(? I forget the number) wires bundled together like this you'd have to derate, but this isn't something you'll have to worry about.

Thank you for this by the way. I got caught up with work and haven't been able to get out to continue working. Cut a piece of scrap and screwed it in. This is what you had in mind? Distance to the bottom of the board is 8".



Then I can just staple wires straight to it, or do the staple+ziptie? When you said 6 wires (and I will check the count) did you mean like one piece of 12/2 counts as 1 2 or 3? I will try to avoid it if feasible so I don't have to worry about it.

Edit:

What is the current approved way to do 3-way lights? Can I have them share on the circuit with the garage door opener? I was planning on doing this, with the power source being the load terminals on the opener outlet:
I think I just answered some of my own question. I need a neutral in every switch box so what I had here wouldn't work. I'll just do a dedicated branch circuit for the lights so I can go panel-switch-switch-light with 14/3-14/3-14/2.

Finally got up on the ladder to do the garage door opener and to no ones surprise:


Replacing it entirely:

H110Hawk fucked around with this message at 00:48 on Oct 14, 2018

Sagebrush
Feb 26, 2012

Our shop has an industrial spot welder that runs on 220VAC. Recently it stopped working -- no functionality at all -- and I've been trying to diagnose specifically what's wrong.

The machine itself is very simple; just a huge step-down transformer with a bunch of different taps to output up to 8000 amps at ~12 volts, and some mechanisms inside to initiate the weld by forcing a heavy copper contactor onto a bus-bar. There's a weld timing mechanism that triggers a solenoid to kick the contactor away after a few seconds but I believe that part is working fine. The problem seems to be with the circuit breaker/power box outside the machine. I measure about 200 volts going into the box from the wall (which I believe is within spec for the 208v you'd see across two phases of a 230v three-phase, right?), but only 91v coming out! The circuit breaker itself appears to be the culprit, not the wiring in the box or anything, because I can see that drop by probing right on the breaker's screw terminals.

So I think we're going to replace the breaker and redo the wiring to the machine and see what happens. But I've never seen this failure mode before, and I'm puzzled as to how it could even happen. What could go wrong with a circuit breaker such that it still conducts electricity, doesn't blow, and isn't apparently shorted, but somehow drops more than 50% of the voltage going in?

Mimesweeper
Mar 11, 2009

Smellrose

Sagebrush posted:

What could go wrong with a circuit breaker such that it still conducts electricity, doesn't blow, and isn't apparently shorted, but somehow drops more than 50% of the voltage going in?

Maybe it's corroded and the insides don't make good contact anymore, or something broke and there's a tiny gap it has to arc across to connect, I don't really know. I'm assuming you already tried flipping the breaker a few times. Does it still feel solid? The parts shop I use likes to rebuild older breakers and that guy could probably tell you exactly what's up but anyway weird stuff like this happens with breakers. I see it a lot.

Mimesweeper fucked around with this message at 17:46 on Oct 14, 2018

Blackbeer
Aug 13, 2007

well, well, well

H110Hawk posted:


Then I can just staple wires straight to it, or do the staple+ziptie? When you said 6 wires (and I will check the count) did you mean like one piece of 12/2 counts as 1 2 or 3? I will try to avoid it if feasible so I don't have to worry about it.

Edit:

What is the current approved way to do 3-way lights?

Yeah, I'd just nail staples to that board. If you have 6 12/2s bundled or more than two going through a hole in a wood frame you'd have to derate, but even if you did it wouldn't probably be an issue for what you're doing. You only need one neutral per room when it comes to light switches, so don't run a neutral to the second of the 3-ways if you don't want.

H110Hawk
Dec 28, 2006

Blackbeer posted:

Yeah, I'd just nail staples to that board. If you have 6 12/2s bundled or more than two going through a hole in a wood frame you'd have to derate, but even if you did it wouldn't probably be an issue for what you're doing. You only need one neutral per room when it comes to light switches, so don't run a neutral to the second of the 3-ways if you don't want.

Thanks! I went and bought some 14/3 and 100' was $61, 250' was $80 so I have more than enough at this point. I am a sucker for unit cost. (within reason, the 1000 foot spoil was like 25¢/foot or something.)

Jealous Cow
Apr 4, 2002

by Fluffdaddy

Jealous Cow posted:

it used to have a screened in porch that ran along the living room with two French doors to access it. That was enclosed in the 40s and turned into two additional rooms, plus a walk in closet and bathroom. Total dimensions of the additional are about 42x15.

The main two levels are about 3400sqft. Attic is another 700ish finished, basement is about 1300sqft with 8 foot ceilings but isn’t totally finished.

It’s got all new plumbing, dual zone HVAC, new kitchen, new bathrooms, but the original layout and finishes. Mostly plaster, original hardwood. It’s amazing and I love it. It’s my colonial loving mansion on .75 acres 3 miles from downtown Cleveland.

Here’s the rest of the sub panel, the main, and my handling live wires trying to figure out the gauge.







Edit:

Here’s where it comes into the garage



And here’s the inside of the box in the garage where it comes in



I have an electrician coming out next Tuesday. I’ll update y’all then.


Had an electrician stop by this morning.

He offered me these options:

1) reuse the existing wires, but he could only give me 20A/240v.

2) Pull new wires using the existing ones, but he said there’s a risk of losing a wire and the max he could do is 40A/240v.

3) Run an overhead line from the house to the garage for a new panel. Up to 100A.

I really don’t want to run an overhead wire, but there’s already coax and fiber running overhead from the garage to the house since the pole with those services is behind the garage, so what’s one more I guess.

Had a 2nd electrician stop by this morning.

He is comfortable pulling new conductors through the existing conduit if he can first get a tape through before pulling the old conductors out. He said he can do up to 90A. Waiting for a quote now.

I figure, worst case scenario: we lose the wire and are unable to get anything through the conduit and have to run an overhead line, which is where I was expecting to go anyway.

shame on an IGA
Apr 8, 2005

Jealous Cow posted:

Had a 2nd electrician stop by this morning.

He is comfortable pulling new conductors through the existing conduit if he can first get a tape through before pulling the old conductors out. He said he can do up to 90A. Waiting for a quote now.

I figure, worst case scenario: we lose the wire and are unable to get anything through the conduit and have to run an overhead line, which is where I was expecting to go anyway.

What is this "lose a wire" poo poo, if one doesn't make it through you pull it back out and start over

Sagebrush posted:

Our shop has an industrial spot welder that runs on 220VAC. Recently it stopped working -- no functionality at all -- and I've been trying to diagnose specifically what's wrong.

The machine itself is very simple; just a huge step-down transformer with a bunch of different taps to output up to 8000 amps at ~12 volts, and some mechanisms inside to initiate the weld by forcing a heavy copper contactor onto a bus-bar. There's a weld timing mechanism that triggers a solenoid to kick the contactor away after a few seconds but I believe that part is working fine. The problem seems to be with the circuit breaker/power box outside the machine. I measure about 200 volts going into the box from the wall (which I believe is within spec for the 208v you'd see across two phases of a 230v three-phase, right?), but only 91v coming out! The circuit breaker itself appears to be the culprit, not the wiring in the box or anything, because I can see that drop by probing right on the breaker's screw terminals.

So I think we're going to replace the breaker and redo the wiring to the machine and see what happens. But I've never seen this failure mode before, and I'm puzzled as to how it could even happen. What could go wrong with a circuit breaker such that it still conducts electricity, doesn't blow, and isn't apparently shorted, but somehow drops more than 50% of the voltage going in?

The breaker contacts are burnt out or there's a loose wire somewhere. More likely a loose connection, contact wear happens all the time with relays and motor starters but breakers rarely get cycled enough to have a problem. Has someone been using it for a switch, daily, for years?

shame on an IGA fucked around with this message at 01:29 on Oct 17, 2018

Special A
Nov 6, 2004

TELL ME WHAT YOU KNOW!

Jealous Cow posted:

Had a 2nd electrician stop by this morning.

He is comfortable pulling new conductors through the existing conduit if he can first get a tape through before pulling the old conductors out. He said he can do up to 90A. Waiting for a quote now.

I figure, worst case scenario: we lose the wire and are unable to get anything through the conduit and have to run an overhead line, which is where I was expecting to go anyway.

Wait, what? Did you ever figure out what size the conduit is? The pictures look like 3/4" at most, that seems a bit small for a 90 amp subpanel circuit.

Jealous Cow
Apr 4, 2002

by Fluffdaddy

Special A posted:

Wait, what? Did you ever figure out what size the conduit is? The pictures look like 3/4" at most, that seems a bit small for a 90 amp subpanel circuit.

He thinks it’s 1 or 1.25 interior.

Sagebrush
Feb 26, 2012

shame on an IGA posted:

What is this "lose a wire" poo poo, if one doesn't make it through you pull it back out and start over


The breaker contacts are burnt out or there's a loose wire somewhere. More likely a loose connection, contact wear happens all the time with relays and motor starters but breakers rarely get cycled enough to have a problem. Has someone been using it for a switch, daily, for years?

Not quite daily, but yes for years. At least for two decades, probably more, people have been using the breaker as the main switch to turn the welder on and off.

I started to pull the box apart to replace it and all the insulation cracked and fell off the wires. Then, even after unscrewing them from the breaker, I couldn't pull the wires (which are like 2-gauge or something, huge) out of the terminals so I think they're fused in place somehow. problem likely identified :jeb:

Once this one is done, it's time to try and figure out why our CNC mill's 320v power supply is only putting out 285v. Seems like there's just something wrong with the electricity in our shop

babyeatingpsychopath
Oct 28, 2000
Forum Veteran


Sagebrush posted:

Not quite daily, but yes for years. At least for two decades, probably more, people have been using the breaker as the main switch to turn the welder on and off.

I started to pull the box apart to replace it and all the insulation cracked and fell off the wires. Then, even after unscrewing them from the breaker, I couldn't pull the wires (which are like 2-gauge or something, huge) out of the terminals so I think they're fused in place somehow. problem likely identified :jeb:

Once this one is done, it's time to try and figure out why our CNC mill's 320v power supply is only putting out 285v. Seems like there's just something wrong with the electricity in our shop

Sounds like the insulation is worn on your shop's electrical wiring, and all the electrons are spilling out onto the ground. You probably have 30V to ground from all the spare electricity in your drains.

Also, get some switch-rated breakers or a disconnect or something.

Spagghentleman
Jan 1, 2013
ONTARIO, CANADA - Was working on tiling my kitchen walls and had all the outlets/switches pulled off the wall and circuit turned off to be safe... When I went to turn the circuit back on when I was done, everything on the circuit still dead. Contact voltage tester shows voltage going out of the romex from the panel, but I can’t find voltage anywhere else in any boxes. Basement (where the main panel is) semi finished, so I cannot figure out the exact path of circuit between boxes.

To make matters worse, this circuit is one of the last original aluminum circuits left from when the house was built in the 70’s, so it’s feeding 6 switched lights (three basement, two kitchen, one outdoor light) a countertop outlet by my range, and my range hood itself. All this is now dead.

On further inspection it looks like whoever screwed down the clamps on the back of one of the outlet boxes did it a *little* too tight on one and shorted the clamp to the hot wire. This may have been like this for decades (yay hidden fire hazard) , but me pulling the outlets out probably justled it enough to break what I’m guessing was the first leg off the branch feeding the rest of the circuit. No matter what I do I cannot get any of the circuit to liven up.

So, I’m thinking most of the light switch and outlet boxes I could get a Romex from the basement up and theoretically separate some of this stuff onto separate circuits with a new copper feed to the panel, HOWEVER the feeds to the lights are near impossible to rerun without ripping the poo poo out of walls. Ideally I would like to leave those as the original aluminum wiring and use proper #63 Marettes and Noalox paste for copper/aluminum connections (or purple twisters... I’m not sure why they still sell those)

I might get an electrician in anyway to see if the aluminum circuit is repairable and give me some advice, but at this point I’m not confident in the existing circuit, even if it was repaired. I’d like to just isolate the switches and outlets to separate circuits and run a separate copper feed for each. Anyone have any comments on how they would do this (or not do this) or if I’m hosed and have to rerun literally everything on the circuit.

kid sinister
Nov 16, 2002
Is there a GFCI on this circuit? You might have another breaker to reset.

Spagghentleman
Jan 1, 2013

kid sinister posted:

Is there a GFCI on this circuit? You might have another breaker to reset.

Nope, no GFCI. All the outlets/switches on this circuit are standard CO/ALR rated for aluminum wiring, no pigtailing on anything.

kid sinister
Nov 16, 2002

Spagghentleman posted:

Nope, no GFCI. All the outlets/switches on this circuit are standard CO/ALR rated for aluminum wiring, no pigtailing on anything.

You might need to update to a GFCI for the countertop outlet then at least.

As for testing your wiring, do you have a multimeter?

Spagghentleman
Jan 1, 2013

kid sinister posted:

You might need to update to a GFCI for the countertop outlet then at least.

As for testing your wiring, do you have a multimeter?

Yup. Neutral to ground is fine everywhere and all my hot wires are open at the switches and outlets, no strange voltages, there is just nothing on any of the hots when the breaker is on. I think the hot feed from the panel to the first box is severed because of the overtightened clamp, so that wire needs to be rerun anyway (no slack at all).

I think Im gonna need to call in a local electrician to answer my question about replacing the feed from the panel with copper (but keeping from the switch to the lights aluminum) and separating the circuit as there’s way too much on it right now.

As for changing the outlet to GFCI, I think it wasn’t because they don’t make a GFCI rated for aluminum. If I reran the feed it would be copper and yeah I’d have no reason for it not to be GFCI.

Spagghentleman fucked around with this message at 03:33 on Oct 21, 2018

kid sinister
Nov 16, 2002

Spagghentleman posted:

Yup. Neutral to ground is fine everywhere and all my hot wires are open at the switches and outlets, no strange voltages, there is just nothing on any of the hots when the breaker is on. I think the hot feed from the panel to the first box is severed because of the overtightened clamp, so that wire needs to be rerun anyway (no slack at all).

I think Im gonna need to call in a local electrician to answer my question about replacing the feed from the panel with copper (but keeping from the switch to the lights aluminum) and separating the circuit as there’s way too much on it right now.

As for changing the outlet to GFCI, I think it wasn’t because they don’t make a GFCI rated for aluminum. If I reran the feed it would be copper and yeah I’d have no reason for it not to be GFCI.

I don't know what they allow for joining copper to aluminum in Canada, but in the US they only allow the gigantic crimper whose name escapes me, or the screw down blocks that need the torque screwdriver that I also forgot the name of.

If you got the multimeter, then you need to start at the head of the branch and work out to the tips, testing for AC voltage. If the wire is exposed in the basement, then you might be able to trace it from the panel to the first box on that branch.

Spagghentleman
Jan 1, 2013

kid sinister posted:

I don't know what they allow for joining copper to aluminum in Canada, but in the US they only allow the gigantic crimper whose name escapes me, or the screw down blocks that need the torque screwdriver that I also forgot the name of.

If you got the multimeter, then you need to start at the head of the branch and work out to the tips, testing for AC voltage. If the wire is exposed in the basement, then you might be able to trace it from the panel to the first box on that branch.

Copalum crimps - and no, it is not the only way you are allowed to splice copper and aluminum. Tyco (they own copalum) paid a lot for internet marketing to spread propaganda about this, basically to say it is the only safe method. Which is bullshit. Proper wire nuts and anti oxidizing paste is allowed pretty much across North America.

Mimesweeper
Mar 11, 2009

Smellrose

Spagghentleman posted:

Copalum crimps - and no, it is not the only way you are allowed to splice copper and aluminum. Tyco (they own copalum) paid a lot for internet marketing to spread propaganda about this, basically to say it is the only safe method. Which is bullshit. Proper wire nuts and anti oxidizing paste is allowed pretty much across North America.

We use noalox in wire nuts and lugs all the time whenever there's copper touching aluminum, and I think you're talking about NSIs for the fancy insulated lug connectors? Those are great for huge wire but a wire nut's fine if it's some small thing.

edit: these things

Mimesweeper fucked around with this message at 21:45 on Oct 21, 2018

Elem7
Apr 12, 2003
der
Dinosaur Gum
Just bought a new house and have 2 seperate circuits with GFCI breakers that keep tripping at what seemed to be random times. Long story short I didn't think both were related but after ruling out what I thought might be causing each to trip I discovered that both seem to go off when we run the "new to the house" 1200w microwave, not every time its run, and thus not always at the same time, which is why I didn't connect the dots before but today they did both go off at the same time and I was able to repeat the trip.

So the thing is, neither is on the same circuit as the microwave, in fact one isn't even in the same panel, it's on a sub-panel, also neither of the other 2 GFCI breakers in the house are doing this, and neither are any of the GFCI outlets, that would all make me think this is a coincidence but since I can reproduce the trip it can't be.

So thread what do you think, am I looking at a bad microwave that's putting a lot noise out over the electrical system in my house(or radio waves)? Am I looking at 2 bad GFCI breakers? Is the wiring in the house just hosed?

The house was built in 1980 so there's no historical gremlins in the wiring. When the problem first came up I considered just replacing the breakers with normal ones and installing GFCI outlets where needed but was concerned I'd just be covering up a potential problem not fixing it. Now that it seems to be the non-connected microwave I'm leaning towards doing just that but wanted a second opinion.

Mimesweeper
Mar 11, 2009

Smellrose
the only thing i can think is the microwave is leaking radio waves that are inducing a tiny current somewhere in the house wiring and that's causing the gfi trip, but i am completely pulling this out of my rear end and it sounds like you live in the twilight zone. what a weird problem

glynnenstein
Feb 18, 2014


My guess would be a shared neutral problem, but it's just a guess.

Mimesweeper
Mar 11, 2009

Smellrose
that's a good possibility and a lot less outlandish than mine.

either way putting the gfci at the receptacles instead of the breakers should solve it. i can't think of any reason why that would be less safe, the breakers are a modern convenience, right?

a gfi is a gfi no matter where it exists in the circuit, it just affects what's being measured as the load side. i don't think the wiring in the walls is going to fall in the bathtub anytime soon.

Nevets
Sep 11, 2002

Be they sad or be they well,
I'll make their lives a hell

Elem7 posted:

Just bought a new house and have 2 seperate circuits with GFCI breakers that keep tripping at what seemed to be random times. Long story short I didn't think both were related but after ruling out what I thought might be causing each to trip I discovered that both seem to go off when we run the "new to the house" 1200w microwave, not every time its run, and thus not always at the same time, which is why I didn't connect the dots before but today they did both go off at the same time and I was able to repeat the trip.

What are the breakers rated for? Not sure why both are tripping, but the tripping itself might be simply due to overloading it and solvable by moving some appliances to another circuit's outlet.

That microwave pulls 10 amps by itself, if you've got other big stuff running intermittently on that circuit like a space heater, big TV, fridge, toaster oven, garbage disposal, etc. you might be getting close to the limit for the breaker when you get a situation where 3 or 4 things try drawing power at once, but rarely enough it hasn't been a problem till you replaced your microwave with a bigger (or less efficient) model. Some stuff also pulls a lot of power for a short moment when it's first turned on (inrush current) so it might say it only needs 5 amps but really needs to be able to pull 10.

Phanatic
Mar 13, 2007

Please don't forget that I am an extremely racist idiot who also has terrible opinions about the Culture series.
Man I do dumb things sometimes.

Note my alarm clock isn't working. Or anything else plugged into that bedroom outlet. Or a second bedroom outlet. Or the overhead lamp in that bedroom. But the other bedroom outlet is fine. As is one of the two outlets in the second bedroom. Hrm.

Downstairs living room, there's an outlet working, and an outlet not working. And an overhead lamp not working.

Random outlets not working, poo poo, I hope one of the two legs to the house isn't down. Open up the panel, nope, everything's hot. None of the breakers are tripped. I start proximity testing the wiring and find some poo poo behind the panel cover that's not good (neutrals tied together with wire nuts instead of directly to the terminals, grounds tied to neutrals with wire nuts instead of the same), fix all that poo poo. Maybe some of those tied-together neutrals opened up and that's why my poo poo doesn't work. Put everything back together, go back and check the outlets. Still no love.

Oh, yeah, poo poo, I changed the 2-prong receptacle behind the TV out for a GFCI when I moved in. And it had tripped for some reason. So it's just weird-rear end 1947 house wiring that had a bunch of random-seeming outlets go dead because they were all downstream of that GFCI, even ones that by any logical wiring would be upstream of it. Probably should have just checked that first.

At least I fixed the bad poo poo in panel.

kid sinister
Nov 16, 2002

Elem7 posted:

Just bought a new house and have 2 seperate circuits with GFCI breakers that keep tripping at what seemed to be random times. Long story short I didn't think both were related but after ruling out what I thought might be causing each to trip I discovered that both seem to go off when we run the "new to the house" 1200w microwave, not every time its run, and thus not always at the same time, which is why I didn't connect the dots before but today they did both go off at the same time and I was able to repeat the trip.

So the thing is, neither is on the same circuit as the microwave, in fact one isn't even in the same panel, it's on a sub-panel, also neither of the other 2 GFCI breakers in the house are doing this, and neither are any of the GFCI outlets, that would all make me think this is a coincidence but since I can reproduce the trip it can't be.

So thread what do you think, am I looking at a bad microwave that's putting a lot noise out over the electrical system in my house(or radio waves)? Am I looking at 2 bad GFCI breakers? Is the wiring in the house just hosed?

The house was built in 1980 so there's no historical gremlins in the wiring. When the problem first came up I considered just replacing the breakers with normal ones and installing GFCI outlets where needed but was concerned I'd just be covering up a potential problem not fixing it. Now that it seems to be the non-connected microwave I'm leaning towards doing just that but wanted a second opinion.

Do you have any old appliances plugged into those GFCIs or outlets protected by them? Older, big motors can trip them with false positives: fridges, washers, vacuums...

Elem7
Apr 12, 2003
der
Dinosaur Gum

Mimesweeper posted:

the only thing i can think is the microwave is leaking radio waves that are inducing a tiny current somewhere in the house wiring and that's causing the gfi trip, but i am completely pulling this out of my rear end and it sounds like you live in the twilight zone. what a weird problem

Honestly I considered it, just Googling the issue online has come up with actual electricians complaining of similar issues, but it doesn't make a lot of sense to me that it's just tripping those 2 GFI breakers, and none of the outlets literally feet from the microwave itself.

Nevets posted:

What are the breakers rated for? Not sure why both are tripping, but the tripping itself might be simply due to overloading it and solvable by moving some appliances to another circuit's outlet.

That microwave pulls 10 amps by itself, if you've got other big stuff running intermittently on that circuit like a space heater, big TV, fridge, toaster oven, garbage disposal, etc. you might be getting close to the limit for the breaker when you get a situation where 3 or 4 things try drawing power at once, but rarely enough it hasn't been a problem till you replaced your microwave with a bigger (or less efficient) model. Some stuff also pulls a lot of power for a short moment when it's first turned on (inrush current) so it might say it only needs 5 amps but really needs to be able to pull 10.

They're 20 amp breakers, and I completely unloaded them for testing purposes and they still tripped. The seperate circuit the microwave is on is, supposedly, a dedicated circuit, though I can't know that for certain, but that circuit isn't tripping at all.

kid sinister posted:

Do you have any old appliances plugged into those GFCIs or outlets protected by them? Older, big motors can trip them with false positives: fridges, washers, vacuums...

I don't think there's a single appliance in the house over 13 years old, the previous owners replaced everything except the washer and dryer but we had newer ones brought with us.

Shared neutral sounds like a possible cause except one of the two tripping panels is on its own subpanel which seems to make that unlikely, maybe I'll just blame it on ghosts. I'll have a look in the panel to make sure there's no obvious buggery in there and just switch from GFI breakers to outlets and call it done. Thanks everyone.

Elem7 fucked around with this message at 04:31 on Oct 23, 2018

Jealous Cow
Apr 4, 2002

by Fluffdaddy
Finally got a quote back from the electrician who is willing to pull new conductors through the existing conduit:

Electrician posted:

Replace the wire in the conduit between the house and the garage with #4THHN.

Install an 80-amp breaker in the main panel in the garage.

Run flexible conduit from the point where the conduit enters the garage to the first floor of the garage.

Install a 125-amp main lug subpanel on the first floor.

Move all of the wiring in the garage to the new subpanel. ($1,095.00)

The existing conduit is 1" interior diameter. According to this chart this would be allowed, as a 1" conduit can take 4 #4 THHN, and I'm assuming he would run 3 #4 THHN and one #6 or #8 ground.

Is there any reason not to do this instead of running a new overhead line? I'm assuming worst case is we gently caress up the buried conduit and have to do the overhead line anyway.

I'm a little lost with "80-amp breaker in the main panel in the garage" and "125-amp main lug sub panel on the first floor". Currently, the line to the garage is served from a 100-amp sub panel in the house basement. Do you think that's what "install an 80-amp breaker in the main panel in the garage" refers to?

Also, how does the price seem? It's about a 50-60' run.

H110Hawk
Dec 28, 2006

Jealous Cow posted:

Finally got a quote back from the electrician who is willing to pull new conductors through the existing conduit:


The existing conduit is 1" interior diameter. According to this chart this would be allowed, as a 1" conduit can take 4 #4 THHN, and I'm assuming he would run 3 #4 THHN and one #6 or #8 ground.

Is there any reason not to do this instead of running a new overhead line? I'm assuming worst case is we gently caress up the buried conduit and have to do the overhead line anyway.

I'm a little lost with "80-amp breaker in the main panel in the garage" and "125-amp main lug sub panel on the first floor". Currently, the line to the garage is served from a 100-amp sub panel in the house basement. Do you think that's what "install an 80-amp breaker in the main panel in the garage" refers to?

Also, how does the price seem? It's about a 50-60' run.

That seems pretty good to me, given you're looking at say 75*4 = 300 feet of wire at a nominal $0.50/foot. (Unless that 60' includes any lateral movement through the garage/house to the subpanel.) They will get it cheaper, but not terribly so, call it $300 out the door with tax including the panel and breaker(s). Then you're looking at a days work to get it all landed and done correctly for $700? Sounds like a good deal. Ask him what happens if you can't get it through.

https://www.lowes.com/pd/Southwire-SIMpull-4-AWG-Stranded-Black-Copper-THHN-Wire-By-the-Foot/50101584
https://www.lowes.com/pd/Southwire-500-ft-6-AWG-Stranded-Black-Copper-THHN-Wire-By-the-Roll/50101714 I guess a 500' roll is more like $0.50/ft, though that is #6 not #4.

H110Hawk fucked around with this message at 20:16 on Oct 23, 2018

Nevets
Sep 11, 2002

Be they sad or be they well,
I'll make their lives a hell

Jealous Cow posted:

Also, how does the price seem? It's about a 50-60' run.

Looks reasonable to me.

I paid about $1300 a couple months ago to replace my existing second floor subpanel and it's service line, no circuits added or replaced. About 5 hours labor for 2 guys (fair amount of drilling & cutting to run the new line), plus 40 ft of cable and a new panel with half a dozen afci breakers.

TooMuchAbstraction
Oct 14, 2012

I spent four years making
Waves of Steel
Hell yes I'm going to turn my avatar into an ad for it.
Fun Shoe
Yeah, that strikes me as pretty reasonable. Hope it works out!

Jealous Cow
Apr 4, 2002

by Fluffdaddy
Thanks, goons!

Mikey Purp
Sep 30, 2008

I realized it's gotten out of control. I realize I'm out of control.
I'm building some bookshelves and want to include four overhead lights. The plan is to use Edison-style LED bulbs that are 6W apiece, so I'm assuming that it would be safe for me to wire those in parallel and plug them into a regular 15A wall outlet, right? Would 14 gauge stranded wiring and a lamp kit be sufficient?

babyeatingpsychopath
Oct 28, 2000
Forum Veteran


Jealous Cow posted:

I'm a little lost with "80-amp breaker in the main panel in the garage" and "125-amp main lug sub panel on the first floor". Currently, the line to the garage is served from a 100-amp sub panel in the house basement. Do you think that's what "install an 80-amp breaker in the main panel in the garage" refers to?

Breakers are there to protect the wire. #4 wire at that distance is rated for 80A when run in conduit underground, so it needs an 80A breaker maximum. 80A panels are tiny garbage, so getting a bog-standard 125A is certainly cheaper, and it has more room for stuff. Since the 125A panel is protected upstream by a breaker well below its rating, it doesn't need its own breaker, so it's going to be a "main lug only" panel. Wires come in the top and go straight to the bus.

The quote seems pretty reasonable. This is not a difficult job, but it is involved and requires some skill, so it's going to take time. Don't feel bad about throwing a couple more bucks this guy's way if he does it quickly and neatly.

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Jealous Cow
Apr 4, 2002

by Fluffdaddy

babyeatingpsychopath posted:

Breakers are there to protect the wire. #4 wire at that distance is rated for 80A when run in conduit underground, so it needs an 80A breaker maximum. 80A panels are tiny garbage, so getting a bog-standard 125A is certainly cheaper, and it has more room for stuff. Since the 125A panel is protected upstream by a breaker well below its rating, it doesn't need its own breaker, so it's going to be a "main lug only" panel. Wires come in the top and go straight to the bus.

The quote seems pretty reasonable. This is not a difficult job, but it is involved and requires some skill, so it's going to take time. Don't feel bad about throwing a couple more bucks this guy's way if he does it quickly and neatly.

Cool, thanks for the info.

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