Panel paint and quality of ground?

[Ignoramus13229]

I installed a subpanel yesterday (see thread "Installed a subpanel!") and am now having concerns. I attached EMT conduit to the panel and subpanel using proper fittings. But the panel and subpanel are painted with some sort of a grey paint. Does that paint conduct electricity? I rely on my conduit to be the ground and, obviously, it needs to have an excellent electrical bonding to the panel and subpanel.

The subpanel is on a 60A breaker.

My common sense suggests that the panel paint is probably conductive and that since everything else is attached in the same way as my new conduit, I should not worry. And yet, I would like a clarification.

Thanks.

i

[HorneTD]

Don't depend on the panel's paint to be conductive because that is not likely to be the case. Take the tip of a large screw driver and scrape away some of the paint before you tighten the locknut. Just back off the locknut to the end of the threads and scape away the paint around the knock out, then tighten the locknut. Put the tip of the screw driver on one of the teeth of the locknut for the connector. Smack the back end of the screw driver a good rap with the side of your lineman's pliers or any similar tool. This will drive the locknut down tight and cause it to bite through any remaining paint on the panel cabinet.

If you really want to make it bomb proof you can buy two bonding bushings and apply one to the connector threads at either end of the conduit run. The bonding bushings are fitted with a terminal lug for a bonding wire that goes to the bonded buss bar in each of those cabinets. In the sub panel's cabinet that should be the Equipment Grounding Conductor (EGC) buss bar. In the service equipment cabinet it would be the neutral buss bar. The use of bonding bushings is only required for service raceways and raceways enclosing conductors with a voltage of over 250 volts to ground. Best practice would be to pull a copper EGC with the circuit conductors in the EMT and terminate it at the bonded buss bar in each panel's cabinet.

-- Tom H

[SQLit]

bond bushings would be required where I live, local jurisdiction.

[Ignoramus13229]

Thanks. My trouble is that I do not see a grounding buss bar on the subpanel (will check again). There is, obviously, a neutral bar, but not the grounding one. I know that I cannot use the neutral bar as grounding bar. Will look again tonight when I come home.

My panel is a HomeLine 6 outlet panel.

i

[Ignoramus13229]

I have none on my main panel. Zero.

i

[Dave Morrison]

Grounding bar is an option, go back to the store where you bought your panel and get it, on a 120/220 subpanel it is required. Dave

[zxcvbob]

I have the same panel in my *detached* garage.

You need to add a "ground kit", and remove the bonding screw in the neutral bar that shorts it to the metal box. You currently have the grounds and neutrals on the same bus. This is OK for a service panel (that's what I have), but not for a subpanel (what you have, but you wired it like a service panel.)

You need to connect the white neutral wires to the neutral bus and the bare/green ground wires to the ground bus.

Best regards, Bob

[Ignoramus13229]

Ah, thanks. I have some buss bars at home (from a demolished UPS), will see if there is any attachment point in the homeline panel.

i

[Ignoramus13229]

I am confused, but that is illegal to have on a subpanel! This item is sold as a subpanel! Wtf?

Okay, thanks for telling me, I appreciate. I was quite puzzled by this and am happy that I decided to ask.

That's for the branch circuits, right?

I will use conduit for ground.

i

[HorneTD]

You have to buy and install the separate ground buss for the Square D product lines. Unlike the GE line they don't have a readily dividable neutral buss bar. With the GE line removing the main bonding jumper leaves the buss bar on one side of the cabinet bonded to the cabinet and the buss bar on the other side insulated from the cabinet so that every cable has to have one conductor run to the other side of the cabinet. I prefer the add on ground buss bars because I can have one on each side of the panel and thus avoid having to run each circuit to the other side of the panel from were it enters the cabinet.

-- Tom H

[zxcvbob]

[snip]

It's is sold as a "Main lug load center suitible for service equipment". It is up to you to install it correctly as a subpanel OR as a service panel.

Don't forget to remove that green screw from the neutral bar. It's threaded into the metal back of the panel box. That's important. Tape the screw inside the bottom of the box somewhere so you don't lose it.

Bob

[Ignoramus13229]

Thanks, I will need to visit HD anyway, to buy outlets and to return stuff, and I will look for grounding bar and ask for advice. I will then use some sort of a clamp to safely connect the conduit with the grounding bar, without relying on the quality of contact between the conduit and subpanel body.

i

[Ignoramus13229]

I see.

I will note the point about the green screw.

i

[John Grabowski]

I thought that you had originally planned to pull an equipment grounding conductor along with your two hot wires and neutral? Using the conduit as a ground conductor is acceptable, but it is also the minimum standard.

[Ignoramus13229]

To be honest, I forgot about it, did not have the bushings etc. Stupid stuff.

I will now go back to what I did, will unscrew the panel adaptors and scratch the painted surface underneath, just to be safer.

i

[J Kelly]

Just go buy the Homeline one. They are less than $10 and fit perfectly.

[HaHaHa]

What's he saving it for???

[e-mail]

[George E. Cawthon]

Then pick up their free literature on electrical panels. Should show you exactly what has to be done for a subpanel.

[zxcvbob]

That's a good question. If he ever takes out the subpanel to put in a bigger one, he'll still have the screw in case he wants to use the old panel as a service entrance for a new building someday?

In other words, it's probably not very important to keep the screw, but I would keep it anyway because I'm a packrat. However, it is important to remove the screw for this installation.

Bob

[Ignoramus22481]

There is no green screw in the neutral bar. I looked at it yesterday. Neutral is not bonded to the box itself. It is a subpanel box, not service entrance.

i