Power Failure!!!

I was psyched the other day when we had a power failure due to heavy wet snow (yes SNOW in NH). The lights went out for 2 hours. Unfortunately it was in the morning so I didn't need to break out my assortment of lights. It did, however, provide an opportunity to test my generator system I installed way back in 1999.

I have a 4KW generator mounted in my tool shed outback with a feedr line into the house. In the house I can switch over 6 circuits to the generator power via a transfer switch.

All worked well and I was able to keep the furnace, fridge, and TV running (plus a few lights to load the genrator down a bit).

I am moving into hurricane ally next summer and am also looking at generators. A friend there actually spent what amounts to a whole years salary for some of us on a HUGE propane powered system big enough to run the whole house including the AC for 2 weeks!

That may be a bit bigger than I need, but I'm definitely planning on getting something like that done. If I'm willing to run not everything in the house and be happy with a gas powered generator I can do it for much less money.

Did you do the transfer switch wiring yourself? That is the part that I'm least looking forward to doing. The theory is simple enough, but I just want to make sure that it's done right since it will be carrying a lot of current! Did you have to get it inspected? If an electrician came out to do it was that part very expensive to get done?

Thanks,
James

Since I live in the northeast, having heat is priority #1. I can do without my central A/C.

Priority #2 is running my fridge and freezer.

Priority #3 is running lighting.

I have 6 circuits which I switch over: furnace, fridge (+ 2 outlets in kitchen), kitchen & outside lights, master bedroom & hallway lights, living room lights & outlets, basement lights.

I have wired up 3 such transfer switch systems. I did the work myself and did not get it inspected. However, I have a background in electrical engineering, along with a healthy respect for electricity.

Once I completed the job, I switched off the main breaker to the house, started the generator, switched over the circuits and then tested (via a volt/ohm meter) for any backflow to the main breaker.

The switches are SPDT (sigle pole, double throw). They are rated for 15 amps each.

I would advise anyone to check their local rules and regs regaridng such an installation. In addition, hire an electrician if you don't feel you can safely and correctly do the job yourself.

I have a sub-panel in my house. As is normal, the house is 120/240V wiring. There is a disconnect feeding the subpanel.

I have a 2-pole breaker in the sub-panel with both poles connected together (it doesn't stay on very long when the panel is powered ).

When the power is out, I open the feeder to the sub-panel (as well as the main) and close this special breaker. A 120V feed from the generator (about 20A available) is fed to the house wiring. The dryer is downstream of this, but it doesn't matter as it won't see any voltage since the wiring is now 0 V across the two hots and 120V in phase from either hot to neutral.

IF the feeder breaker AND the main aren't opened, the pole transformer will short the two sides together and probably trip the breaker, but the placards say both the feeder AND the main must be open before connecting/starting the generator.

I think the really good (but more expensive) way to do this is a 100A manual transfer switch and a sub-panel for all the generator loads downstream. Then you can use any (reasonable) sized generator.

Someone I know actually backfed the grid with 120/240 and powered some of his neighbors during an outage--but that is VERY dangerous for people working on the lines, as your 120/240 will be transformed up to 2400V at least on the HV side...shocking for someone not expecting it.

Please make sure you're comfortable doing what you're doing and that safety is your primary concern.

Cheers,

Richard