ECN Forum Forums General Topics of the Trade General Discussion Area transfer switch

Doing generator/panel transfer switch tomorrow, 200a res.,Never did one and my partner(who has) can't be there.Any tips?

De-
They're fairly self explanatory, read the instructions (sorry, I know that's NOT the electrical way ) it's pretty much Normal line in, Line out, Emergency line in. You didn't say manual or automatic, auto means you have a start signal to genset, transfer signal from source to contact (which is sometimes pre-wired). You'll do fine, take a deep breath, another drink of coffee, and dig in.

Make sure you have the correct transfer switch for the type of generator being installed.

If the generator neutral is bonded to the frame by the manufacturer, a transfer switch that breaks the neutral (three pole) is required.

Here is a basic diagram for a typical generator with a bonded neutral.



However, if the generator neutral is not bonded to the frame, a transfer switch with a solid neutral buss (two pole) is should be used.

Here is the basic diagram for a typical generator with a floating (not bonded) neutral.



Hope this helps,

Ed

ElectricEd, is the use of the 3 pole switch to protect the generator, or the lineman? I have installed a couple of these and have always thought that breaking the neutral would seem the safest for the lineman. The people at Ronk swear that you only need a single pole switch in a single pole application, not to mention the extreme difference in price. What do you think?
Thanx, John

No, John. The neutral must be switched to prevent the equipment bonding conductor (EGC) from being in parallel with the neutral in installations where the generator neutral is bonded to the frame.
This would permit the neutral (unbalanced) current to flow on the EGCs which is a NEC violation.

Note also that in these cases, where the neutral is switched, the generator neutral is required to be earth grounded.

Ed

[This message has been edited by electric-ed (edited 08-24-2002).]

Ed,

Again, great work on the Schematics!!!

Scott S.E.T.