Help with new 220V sub panel circuit

darkbreeze

I was kind of wondering, why is ok for the neutral and ground bus's to be bonded, connected together, in the main panel, but not in the sub panel? Just FMI.

TTW

Why isolate the neutral in a sub panel?...
The neutral is only bonded to ground at your service panel. At all other points throughout your house, there is no connection between the bare (or green) grounding conductor and the white neutral conductor. Under normal conditions, the grounding conductor carries no current. No current means there is no voltage drop along it, therefore anything "grounded" to this conductor is at the same potential (voltage) as ground. If you bond the neutral and ground at the sub panel, than stray currents from the neutral return could go thru the equipment ground on the electrical devices fed from this sub panel. If you isolate the neutral and ground at the sub panel, than any currents would go back to the main panel, and go to the service ground. The main panel is where the neutral and equipment ground should be bonded.
If you install a sub panel outside the building from the main panel, than you will need to drive a ground rod at this panel. A single branch circuit run to another building is not considered a sub panel.

From: http://masterslic.tripod.com/FAQ-2/18.html

darkbreeze

I also wanted to just say thanks to those of you who are attempting to help me with this problem. I left messages on several other forums and several days later have received no response on any of them. So thank you for your help.

brric

The TLM 1212 will accept GE THQL or THQP breakers. THQL are 1" in width and THQP's are 1/2" in width. It might be possible to replace several THQL's in the main panel with THQP's thus freeing up a space for a 2 pole THQP for the compressor.

darkbreeze

Here's a pic. You tell me, but I think everything is already reduced as far as it can go. Please let me know if I'm wrong.

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JuzRick

Brric::: smart ***.. i never said install a subpanel. I asked if he had a combo panel outside he could utilize for the 30 amp brkr!

brric

Bottom right there are 2 THQP's. Above them there are 2 THQL's. The 2 THQL's could be replaced with THQP's and a 2 pole THQP could be placed between them.

JuzRick

Yes:: that can be done utilizing a 20/20 duplex brkr! Then you will have space for that 30 amp. I've done it. Learned it from a ME(Master Electrician). Passed inspections tooooo(if/when required)!!!!

JuzRick

Brric::: I will say here it is permitted. I know in some City(ies).. its not allowed. Not meaning isn't right. Some area's are stricter than others on certain situation- not saying that it is a safety violation! If pass inspection.. i consider it acceptable.

Oso954

If I read your original post correctly, this is a detached garage.
I assume it already has at least one circuit already feeding it.

You should be installing a larger subpanel and feed so that all of the garage requirements are served from the single subpanel.

k_buz

You do not have to run 4 conductors. If you use metal conduit, the conduit itself is the equipment grounding conductor and there is no need to run a ground.

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jbfan

I know that doesn't mean it was correct per code but I just want this to work for now, not worried about it being a licensed installation or being able to pass an inspection.

This right here tells me he's going to do what he wants.
If he has a circuit going to the garage, he can not run another!

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Yes I am a Pirate, 200 years too late. "Jimmy Buffett"

JuzRick

Well yes.. to have it match up. without it, the compressor wont start after plugging it in starting it.

The only exception you would have is on the ground side. the compressor will still start tho.

I still ground it... for you just may utilize the circuit for something else in the future. You just never know!

frenchelectrican

I was reading thru on this one and I will address to the OP .,

Seince you mention you want to run the air compressour the only way you can do this in legit way is you have to ditch the exsting circuit and run a new circuit to the detached garage with new subpanel and one circuit for your air compressour and other circuits as needed in the garage.

There are few legit metholds you will have to use .,


A ) PVC conduit buried in the ground that have to be 18 inches deep and use 1.25 inch pvc with 4 conductors 3 X 6 awg conductors and 1 X10 gauge conductor ( 6 awg black, red , white and 10 awg green unless your code required the green to be #6 then do it.)

B ) Direct bural UF cable 6-3 UF cable that have to be 24 inches ( unless other depth per your local codes ) but you will need larger conduit due the 6-3 UF cable is pretty wide so therefore 1.5 inch is bare minum for riser for protection.

I rather just run all the way thru with PVC and with THHN/THWN conductors and be done with it.

Of course you will need two ground rods as well.

Again., keep the netural and ground seperated.

Merci,
Marc

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The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

brric

I'm confused. Why won't the compressor start?