Question for those literate in wiring panels - can I visually see if my panel is wired wrong?

[hezagenius]

I had my garage wired with a 100A panel over the summer and bought a CUBE controller to jump headfirst into eBrewing. The panel is not GFCI but the breakers are GFCI. I got around to using the CUBE a few months ago and the 240V outlet worked fine for the element but any time I had something plugged into one of the 120V outlets and turned it on, it would trip the GFCI. OK, I figured something was goofy inside the CUBE. I contacted Auber and they said if the 240 is working but the 120 trips the GFCI, there's a good chance the breaker is wired incorrectly. They said to have the electrician look at it to verify the wiring is correct before worrying about if the CUBE is the issue. Fair enough.

The troubleshooting guide they have says if the 240 is good but the 120 isn't, it is possible the neutral wire is not wired correctly. The coiled white pigtail should go to the neutral bus. The neutral from the wall outlet should be connected to the terminal on the GFCI instead of the neutral bus. If the neutral wire from the wall outlet is connected to the neutral bus, it will trigger the GFCI for 120 devices.

I'm no electrician and do not want to die for this hobby. Is it possible for me to visually diagnose the stuff in bold font above? If I turn off the breaker on the main panel, can I unscrew the faceplate on the garage panel to see if this is hooked up correctly? My electrician is dragging his feet and if I can see it's not done correctly, I'll just hire another guy to come over and rewire it.

 

[Tobor_8thMan]

If a licensed electrician wired things I doubt they miswired (swapped white/neutral for hot/black). This is very dangerous and life threatening to assume things are miswired and hook up something believe things are miswired.

We get 240 from having the 2 120 wires connected. Maybe something came loose?

I HIGHLY recommend having a licensed electrician visit to check the control panel. Not worth the risk. 240 will kill. 120 will kill.

When they are done, offer a few homebrews. Who knows, perhaps a discount...

 

[schematix]

Neutral isn’t wired right. Ask me how I know.

It’s diagnosable with a picture inside the panel.

 

[hezagenius]

Neutral isn’t wired right. Ask me how I know.

It’s diagnosable with a picture inside the panel.

Ok. I assume I can turn off the the 100A breaker on the main panel and remove the plate covering the breaker wiring on the garage panel to look?

 

[LittleRiver]

If a licensed electrician wired things I doubt they miswired...

I once had a licensed electrician connect a $20K vacuum pump to power because I didn't want to risk doing it myself (though I knew how). He got it wrong and fried the pump motor. His insurance company had to buy a new one.

 

[day_trippr]

A licenced electrician almost killed me. He ran a 60 amp 3-phase drop under the raised floor in a data center for a new mainframe memory unit, swapped one of the phases with the big honking case ground inside the connector housing, and didn't bother to tag the drop with its panel and breaker number.

When I showed up a few days later and went to fish the drop up to plug in the new crate I grabbed it by the protruding cord, the connector (huge Russellstoll cast aluminum beast) flopped around, banged against the raise floor grid, and KABOOOM! HUGE flash, lots of heat and bits of slag sprayed around, and I ended up about five feet away. And literally ready to murder someone.

I was wearing shorts and my legs were rubbing against the metal floor grid. Had I grasped the connector by the housing there's a good chance you'd have never read this...

Cheers!

 

[schematix]

If it were me i'd have no issues taking the cover off with the power shut off at the main panel.

However i'd also use a meter for everything and don't take for granted the panel is completely de-energized.

But if you really have no clue then either read up on household wiring to where you are comfortable, or leave it to someone else, who may or may not know what they are doing too. But they are in the line of fire not you.

If you google '240V GFCI with neutral' you'll see the wiring. The issue is likely that the neutral is coming off the main panel neutral and not off the GFCI's neutral. When you run 240V the lines are balanced so the GFCI doesn't trip, but when you use a 120V circuit you unbalance the 2 hot lines and cause it to trip.

 

[mongoose33]

The most important rule about working w/ electricity is this: keep one hand in your back pocket while working on it. That way if you happen to touch anything bad with one hand, the other isn't touching anything that would allow a circuit to be completed through your chest.

 

[augiedoggy]

also its better to work with left hand since the right is a direct path to heart according to the electrical safety certification class I have to retake every year.

if your main is off and you verify the panel is no longer powering anything your safe to work on it.

 

[hezagenius]

All I really want to do is take off the faceplate covering the panel to see if the pigtail is going to the bus and the neutral wire from the outlet is going to the breaker, but you guys are freaking me out. Since the electrician that did it is dragging his feet (and assured me it is wired correctly), I sent an email to the general contractor to see if they can send an electrician. I feel like this is a 5 minute diagnosis and a 10 minute fix, if that. I have no intention of attempting to fix it myself, or even touch the wiring.

 

[mongoose33]

All I really want to do is take off the faceplate covering the panel to see if the pigtail is going to the bus and the neutral wire from the outlet is going to the breaker, but you guys are freaking me out. Since the electrician that did it is dragging his feet (and assured me it is wired correctly), I sent an email to the general contractor to see if they can send an electrician. I feel like this is a 5 minute diagnosis and a 10 minute fix, if that. I have no intention of attempting to fix it myself, or even touch the wiring.

You can take the cover off the panel without putting yourself in danger. Just remove the screws, then carefully remove it. Putting it back is the reverse, easy-peasy.

Just don't touch anything inside you don't understand.

Unless it's a rats-nest of wires in there, you should be able to tell what they've done. Use a small flashlight to help you trace the wires if necessary.

 

[schematix]

You can take the cover off the panel without putting yourself in danger.

In general this is true BUT there are lots of horror stories out there about some dumbfsck electrician who tied a hot to the ground, and the panel wasn't grounded so the chassis was hot.

Guy i worked with on one of my first installations described "racoon eyes" he got when fuses turned to plasma in front of his face. His safety glasses were the only reason he can still see today. Chassis was hot and someone using a wrench turning a disconnect bumped the hot cabinet and poof! Also why you look away from a panel when turning it on.

This story is meant to be cautionary. The tools exist to make the professional very safe, even when someone screws up. But if you don't follow good practices eventually you're gonna get zapped because of someone else's mistake.

 

[postalbunny]

Was going to say i had a similar issue initially with my GFCI breaker, the curly-queue white wire has to go to the neutral bus bar. If you're worried about hurting yourself just hire another electrician to dbl check the work... call up some guys, explain the situation and ask how much they'd charge to dbl check it. If i got your call, I'd prob charge you about an hours worth of work and liken it to 'easy work' like replacing a fuse or something.

 

[hezagenius]

Electrician came today to look at it and the black neutral wire from the outlet was not going to the breaker. It was maybe connected to the bus, or maybe something else. Couldn't tell for sure. But now it goes from the outlet to the breaker and everything seems to be fine.

 

[schematix]

neutral wire is never black

 

[audeyoe]

neutral wire is never black

SHOULD never be black. Don't take for granted that the last person wired things right.