residential standby generator

That is a fairly standard configuration.

That is the usual method. the standby panel is mounted next to the normal panel. The load wire for the circuit is removed from the breaker and attached to the load wire coming from the transfer switch. The supply side wire from the transfer switch is attached to the breaker. the standby panel has breakers for each circuit and a transfer switch for each circuit. More expensive systems will automatically start the generator and switch over the loads without human action needed.

Depends on your AHJ. The question is what will your local electrical inspector accept.

--Dale

A more elegant solution is to make your emergency panel a sub from the existing, pull those circuits out and swing them over. Then the only connection to the existing is the feeder via the transfer switch. They have a transfer/sub panel all in one box so the only issue is moving the 6 circuits. The limitation is probably wire length and where you have to mount the transfer panel. Just be sure it still remains "readily accessible". That means you don't need a ladder to reach the breakers and that you have "working space"..

Thanks for the replies....but I guess I need to be specific.....

My aging memory tells me that

1. Somewhere in the NEC it prohibits splices in a panel box. Obviously, in many installations of this type, extensions of the conductors will be necessary.
2. Somewhere the code also prohibits using a panel as a raceway, which it would become if splices were made within it.

So, to be truly compliant, would I need to set a box next to the Panel, pull the circuits in question out of the normal panel and into the 'J' box, splice them there and then to the emergency panel?

I do industrial and commercial work, so I am rusty on this residential stuff. And I also see what a lot of folks 'get away' with (ugh).

Some local utility companies will provide you with electrical diagrams on how to connect a standby generator. I suggest that you contact them first.

There are other approaches. "My" electrician proposed replacing my obsolete panel (it used Bulldog breakers) with a panel that via a mechanical interlock has a built in transfer switch.

I didn't "bite," but it got me thinking.

I kind of like the idea of putting the "dual feed" panel next to the old panel (it is still functional and safe, it just isn't "supported" with new breakers anymore.) BOTH panels would be fed from the utility. (NEC says you can have up to SIX panels.)

Depending upon the size of the backup generator I can transfer more circuits to the new panel.

With a manual transfer switch, you don't KNOW when the power comes back on.

Most modern cabinets for panels have enough space. The cabinet for your old GE Bulldog may not. If you avoid exceeding the seventy five percent fill limitation you'll be alright.

-- Tom H

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residential

(ugh).

You dont need splices to do that... what you do is remove the circuits you want on the emergency gen set to a sub panel. So there it is hanging in the air with no power supply to the sub panel.

You then fit a 50 amp two pole breaker in some of the empty spaces left by the circuits moved to the sub panel...and run your power from the new 50 amp breaker to the sub panel.

Your transfer switch goes in the line between the two panels. No splices. Actually its about the only way you can do that load separation sensibly. ...not a trick strategy its how its normally done.

Phil Scott

| You dont need splices to do that... what you do is remove the | circuits you want on the emergency gen set to a sub panel. | So there it is hanging in the air with no power supply to the | sub panel. | | You then fit a 50 amp two pole breaker in some of the empty | spaces left by the circuits moved to the sub panel...and run | your power from the new 50 amp breaker to the sub panel. | | Your transfer switch goes in the line between the two panels. | No splices. Actually its about the only way you can do that | load separation sensibly. ...not a trick strategy its how its | normally done.

Are you going to be bonding the neutral to the grounding wire at the generator? If you are, then you will have created a bond that will allow neutral currents to run over the groundING wire. That is, unless the transfer switch is a 3-pole unit that also switches the neutral wire.