Generator question (household wiring to be more accurate)

[Gary Fowler]

If you want a whole house generator, a 20KW should suffice. You would still need to put in a load shedding transfer switch so everything could work with electric heat being the killer. If you don't have that (you could just not put that breaker in your transfer switch) 20KW should run everything else with the load shedding switch taking care of switching the load off of a major appliance like AC before allowing a stove top to start up or water heater for example.
I don't under stand how you plan to use the 50 Amp service to feed your whole house, it is likely just feeding off one side of your 200 amp service so only the stuff on that side would work by backfeeding even if you got it hooked up.
Your best bet is to decide what you want to use or need during an outage, get your brother in law to wire in a transfer switch and hook up those circuits while powering the transfer switch with the appropriate size wire to the circuits from your genset. IF you look at LickLog's data plate for his 7000 watt propane fired genset is says it will run 8 hours @50% load on 20 gallons of propane. That is a little higher but near the same consumption per KW (2.5 gph) as what I priced for the 20KW. Diesel of course might be a little better but still a lot per day.

I looked at a whole house unit when I build my new house but ultimately decided that it was too expensive to run on propane (no NG service here) even for a 20 KW set. Propane was over $2 per gallon and that genset ran 4.8 GPH at 50% power IIRC so about $10 per hour x24 hours= $240 per day. Instead I just bought a 10KW with 8000 watts continuous to run when I needed it, bought a catalytic propane heater for heat and so far never used either.

 

[Opti-Mist]

Richard, mine is generally the same as you propose. I have a 7500W generator feeding 30 Amps via #10 wire to the 100 Amp panel in the pole barn, which in turn back feeds to the 200 Amp service panel in the house. This carries the well pump, H2O heater, furnace, etc. We don't try to run the A/C. No issues with this setup as long as the wire is appropriately sized which your brother will ensure.

 

[Tractor Seabee]

Richard, you really need to go to your brother with hat in hand and get his help instead of separating the wheat from the chaff you will get here. Previous threads on this subject get very tedious to those who really know the answer. Also you may have exceptions and local challenges we cannot see much less envision.

Ron

 

[Tractor Seabee]

Richard, you really need to go to your brother with hat in hand and get his help instead of separating the wheat from the chaff you will get here. Previous threads on this subject get very tedious to those who really know the answer. Also you may have exceptions and local challenges we cannot see much less envision.

Ron

 

[Ken45101]

We rigged (correction, "HE" rigged) his generator to the second panel and backfed the main panel (main breaker was off)

While that works, it is flat out illegal and dangerous, lethally dangerous. What if someone (wife, teen, whomever) decides to "check to see if the power is back on" and flips the main breaker? It could kill someone working on the downed power line. Code requires it to be physically impossible for someone to make a mistake and backfeed the incoming line.

As for how much power that #6 can handle, it depends on how long of a run it is. Long runs reduce the voltage. What works for a 50' run will be significantly reduced with a 500' run.

 

[check]

If you were going to spend all that money on the new 20 kW generator, why not spend a few extra bucks and get an automatic transfer switch?

 

[Gary Fowler]

If you were going to spend all that money on the new 20 kW generator, why not spend a few extra bucks and get an automatic transfer switch?

All of the whole house 20KW generators I priced came with an automatic transfer switch included in the $4500 price tag. They generally cost about $650 if bought separately.

 

[rhunt]

Richard, we need to know several things in order to answer your question. However, my feeling is, hire an licensed electrical contractor to due this job, with proper permits. I know many men who call themselves electricians and have been doing electrical work for the past X amount of years and they mostly do not know what they are doing when it comes to generator hook-ups, etc. Just saying! Now, first thing, you need 4 wires from your main house panel to the generator. They consist of 2 hots, 1 neutral and 1 ground. If the run from the house panel to the generator is rigid galv. conduit (RGC) then the conduit can be used as the grounding conductor and then you would need 3 wires, 1 for the neutral and 2 for the hots. I am assuming this run is mostly underground and if it is, then the conduit must have a depth of 2 feet from the top of the conduit to the finished grade. This depth can be less (18") but for this conversation 24" will suffice. Hope this will activate the little gray cells. Bob

 

[check]

All of the whole house 20KW generators I priced came with an automatic transfer switch included in the $4500 price tag. They generally cost about $650 if bought separately.

$4500!! That's a steal! Buy it!

 

[check]

Richard, we need to know several things in order to answer your question. However, my feeling is, hire an licensed electrical contractor to due this job, with proper permits. I know many men who call themselves electricians and have been doing electrical work for the past X amount of years and they mostly do not know what they are doing when it comes to generator hook-ups, etc. Just saying! Now, first thing, you need 4 wires from your main house panel to the generator. They consist of 2 hots, 1 neutral and 1 ground. If the run from the house panel to the generator is rigid galv. conduit (RGC) then the conduit can be used as the grounding conductor and then you would need 3 wires, 1 for the neutral and 2 for the hots. I am assuming this run is mostly underground and if it is, then the conduit must have a depth of 2 feet from the top of the conduit to the finished grade. This depth can be less (18") but for this conversation 24" will suffice. Hope this will activate the little gray cells. Bob

I also had to bury a 14/2 conductor for the battery charger and carburetor heater, since ithe temperature gets down really low in the winter where my generator is.