New electrical question

[Junkman]

I knew about the grounding and isolated grounds. Am I correct that the white wires are the ones that are grounded to the rods in the earth and the bare copper ones go to the white wire coming from the pole at the street? Also, the panel that I want to use has a main breaker in it. Is it OK to wire from the main panel to this main breaker in the sub panel? I would like the ability to turn off the sub panel when I am connecting wires in it. Next question, is it OK to mount the sub panel with the main breaker at the bottom? This will make it easier for me to connect the sub panel to the main panel. Last question.... do all the sub panels isolated grounds get tied together at the ground rod in the earth or do each of them require their own grounding rod? Thanks..... Junk

one more last question.. is the bar that the bare copper wires are tied to also isolated from the metal breaker box like the isolated ground buss bar????

 

[SPIKER]

Hey Junk:

the bare copper wire is the one that should be connected to the copper rod driven into the ground.

you do not need sepperate ground rods for each panel when they are in the same house only when they are in different buildings.

the sub panels usually have 2 Neutral/ground bus bars one on each side with a large metal bar connecting the two. one of the two should be dirrectly bolted to the metal cabinate/panel and the other one will be instulated mounted on plastic. you remove the strap that connects the two bus's together then attach all the bare / green wires to the one that is bolted dirrectly to the panel/cabinate and all the white wires to the other one. then run 4 wires form the main panel to the NEW SUB panel. 2 wires are hot wires to the sub panel main breaker is oK or to the lugs if you so wise as long as there is a breaker in the main control panel feeding the sub. One neutral wire white to the insulated bus and one green wire/bare wire to the grounded bus. and you will have hot panel when the main breaker in the main panek is turned on and the main breaker in the sub panel is turned on.

be sure to ballance the load on the sub panels so that when you are running all the stuff planned on it that the leg to leg amperage is nearly the same.

Mark M

 

[Junkman]

Spiker.... I want to make sure that I understand this correctly. Here is a picture of the panel that I need to separate the whites and the bare coppers. I intend to put a bus bar on the left that will go to a ground rod under the panel that is hammered into the ground. The large wire that is painted white comes from the street pole. Does the white wires get hooked up to that white painted wire and the bare copper wires go to the ground rod that is under the panel? If I read your previous post correctly, the bare copper wires will go to the white painted wire. This bar is also bonded to the metal cabinet. Do I remove that bond? If I do, then there is no grounding of the metal cabinet, is that correct???? thanks for all the help..... Junk...

 

[techman]

Maybe I can step in here. If the picture is your main panel, the white and bare can be mixed since the two bars are connected together. On the sub panel, one bus bar is connected to the metal box. This is the ground bar and only the bare wires should be connected to it. The other bus bar will have the incoming white connected to it and you will land all of the white branch circuit wires to it. Remove any existing jumper between the two bus bars.

As for using an existing box with a main breaker, no problem. Just make sure that the breaker in the main panel feeding the sub is sized for the feed wire to the sub (or the wire is sized for the breaker).

On the main panel, the ground rod is connected to the ground (bare wire) bar, and the incoming neutral (white) to the other bar. In the main panel, where the ground rod would connect, the two bars are connected together, as mentioned earlier.

paul

 

[Junkman]

Thanks... after doing a upgrade to underground service with a 200 amp disconnect last spring, the main panel is now considered a sub panel and I need to separate the wires in there also. You might say that the main panel is also known as the sub panel in this installation. How about putting the main breaker at the bottom instead of the top..... does it make any difference. It will be easier to wire if I do it this way. The second sub panel is going alongside (10" away) of the main/sub and this is the reason..

 

[Junkman]

What size copper wire would I use from the ground bar to the grounding rod for the 200 amp service and for the 100 amp sub panels??? I want to get this right the first time and make sure everything is safe. I have done wiring before, but this is outside of my area of knowledge......... thanks...

 

[techman]

junk:

For a residential installation, code requires the ground rod for a 200 amp service requires a #4 ground conductor. Solid copper or copperclad aluminium wire can be used.

For the sub panel, the code normally requires that the ground conductor be one size smaller than the feed conductor size, so if the main conductor is #6, the ground is #8 or larger. If you buy a 6/3 cable with ground, the appropiate ground size wire is included.

paul

 

[notamustang]

</font><font color="blue" class="small">( How about putting the main breaker at the bottom instead of the top )</font>

This is fine as long as you the panel will accomidate the breaker. Basically as long as the panel cover and the deadfront (the piece that covers the breakers) are still doing their job. /forums/images/graemlins/cool.gif

 

[HammerFour]

Junkman, if your subpanel ( old main panel ) and new main panel are in the same building, the ground and neutral buses can be tied together.

You only need to seperate the ground and neutral buses on subpanels in seperate buildings which have potential ground differences.

 

[Inspector507]

Check your local/national codes before quoting something like that.... /forums/images/graemlins/grin.gif