OT: generator for ice storm

[Duane Attaway]

On Tue, 4 Jan 2005, Brad wrote:

> This is way off topic, but related to a recent thread.  I have a 5500 
> watt generator that might see some usage tonight or tomorrow.  In the 
> 2002 ice storm I fed the 240 out of the generator and into my ac 2 pole 
> breaker to feed the electrical panel in the house.  I threw the main 
> while doing this and had no problems.  Now, thinking about the coming 
> storm I was looking at the possibility of doing this again.  Everything 
> you read on the the Internet says you are crazy for doing this and risk 
> frying your generator, killing a linesman, or burning down your house. 
> My question for you electrical whizzes is if I absolutely, positively 
> remember to throw the main when doing this, what are the real dangers 
> then.  Is it just warned against because someone _might_ forget to throw 
> the main or are there dangers even if the main is thrown.

Just don't feed your entire house off a 18 guage extension cord!

I'm used to fixing electrical disasters at work, so I have an eye for what 
doesn't work.  Use connectors rated for at least the circuit breaker 
rating, use heavy guage wire (10 guage is plenty for 30 amp overload) and 
route your wiring neatly and you should have any problems.

I'm not sure if a generator hooked up to a live circuit will sync or not. 
The peaking generators I worked with only kicked the main breaker when it 
was synced at engine temperature.  I guess if a circuit breaker the size 
of a television can protect a 1,600,000 watt load if it was out of sync, I 
don't see your house blowing up over an comparibly insignificant 5,500 
watts.

If you are feeding your neighborhood, your generator's circuit breaker is 
likely to trip.  That's a large load.  Worst case you could burn out every 
electrical device in your neighborhood, because all their electric motors 
are off frequency and undervoltage.

If you have a voltmeter that measures frequency, be sure to check that it 
doesn't get too carried away from 60Hz and 120 volts.  AC motors 
syncronize to the frequency.  70Hz may start to magnetically slip inside 
and burn up, especially if the voltage hasn't been increased to match the 
frequency curve.  If the generator's frequency can't be controlled, you 
will be witnessing a fun science experiment in action.

UPS supplies are nice with a generator.  Have them next to important 
things like your televisions and lights if you need to refuel.  If you 
have a really big UPS, you can cover the whole house.  Such units complete 
with switchgear are becoming popular surplus items.  One of the guys on 
the list gave me a few 10KVA units (3,000 pounds each!)  They recreate a 
perfect sine wave at an exact voltage and frequency of your choice, 
regardless how wild your generator gets.

Its nice running everything in the house when the power is out.  Being in 
the dark with the one you love in front of the fireplace may be romantic, 
but it becomes a chore real quick!

-=Duane
http://dattaway.org