ground and common tied together in sub panel?

[Eminem]

I noticed in my sub panel, that on 2 circuits, the ground wire was attached to the neutral bar. I thought in a sub panel, grounds and neutrals were supposed to be seperated. I asked someone who has always given me good info and he said since its the first disconnect for the circuit, it was OK.

Would it matter if the circuit was 120 or 240?

I just want to see what the gurus say here

 

[PharmaCan]

In a sub-panel your grounds should be isolated from your neutrals - no mixing them on the bus bars.

A 240v circuit doesn't have a neutral. (There might be a neutral in a 240v circuit for something like a stove that has a 120v clock, but 240v itself has no neutral.) A 240v circuit should have a ground, because that's a safety thing. Regardless, keep the grounds with the grounds and the neutrals with the neutrals.

PC

 

[Bulldog11]

Your main panel should be bonded. So, yes. Your ground and your neutral should be connected in your main box only.

 

[Fluorobuds]

I was always told to keep them separate in a sub-panel as well. I believe that in a sub panel they should not be connected and it is against code. Only in the main box should they be connected.

 

[Eminem]

In a sub-panel your grounds should be isolated from your neutrals - no mixing them on the bus bars.

A 240v circuit doesn't have a neutral. (There might be a neutral in a 240v circuit for something like a stove that has a 120v clock, but 240v itself has no neutral.) A 240v circuit should have a ground, because that's a safety thing. Regardless, keep the grounds with the grounds and the neutrals with the neutrals.

PC

I know 240 doesnt have neutral, just wondering if 120 and 240 affected the rules about neutral and grounds.


I was adding a DP breaker to add another light and noticed the ground wires on the neutral bar. I did wire my circuit right

Now the ground wires connected to the neutral bar are short. I can twist them onto ground wires passing by, or use a twist connector to extend the grounds and make the connection to the ground bar. I guess use the twist connector and extend it would be the best huh?


I understand, dont mix neutral and grounds in the sub panel. Can you explain why? I dont doubt you, I just like to know these things and I may have to explain this to someone else as well.


Thanks

 

[Fluorobuds]

No prob Em, I found this online for ya, explains it better then i could prolly

Why not connect the neutral and ground at other points in the system?

Because if a neutral wire became disconnected (I've seen it happen), the return path for electric current could be along a ground wire. While that itself may not be a hazard, if that ground wire also became disconnected somewhere, parts of the ground system could be energized. That's not EVER supposed to happen.

The neutral wire is essentially a "low-risk" return path for the electric current in that branch of the system. All of the neutral wires all have the same electrical potential... nothing. At least, no potential compared to ground. There is, of course, 120 volts of potential difference between a neutral wire and any hot wire in the residential system.

If you touched the metal part of a live neutral wire you should not receive a shock. (But don't try it!) By tying the neutral to ground at one point, half of the conductors (in a typical 120 volt circuit) have no dangerous electrical potential. Of course, the hot wires are still dangerous.

http://www.hammerzone.com/archives/elect/panel/sub_panel/01/new.htm

Sounds like alot of "ifs" haha, but I guess that's how it's done.
I'm guessing you're right about using wire nuts to add on the extra length of wire to get it to the ground bar. Good luck with it, it sounds like you have it figured out

 

[Bulldog11]

240 can and usually does have a neutral

 

[PharmaCan]

240 can and usually does have a neutral

No it doesn't. I'm sorry, but you are wrong about this.

PC

 

[Eminem]

No it doesn't. I'm sorry, but you are wrong about this.

PC

I have wired up a compressor, wall unit A/C and plenty of lights and none have a neutral. Two hots into a DP breaker, and a ground.

I have to go with PC on this

Thanks for the info Fluoro

 

[The Southpaw]

I have wired up a compressor, wall unit A/C and plenty of lights and none have a neutral. Two hots into a DP breaker, and a ground.

I have to go with PC on this

Thanks for the info Fluoro

You are both correct, sort of,, the service to your house has 2 120 lines and a neutral.. the voltage BETWEEN the 2 120 volt lines is 220v. So the third wire in a 220v circuit can be thought of as a neutral .it is just not a neutral in a 110v circuit box way..