Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It only takes a minute to sign up.
Sign up to join this community
I want to wire an 8 kw standby generator to power my home furnace (120 v, 20 amp) automatically in case of a power outage.
The generator can be purchased with and without a transfer switch.
Is there important circuitry in the transfer switch (e.g., that starts the generator every week so)? Or, can I just wire the furnace to a double pole double throw relay, for $20 or so?
(I plan to run a few extension cords to power lights, refrig, etc. but I will hook those up manually.)
The input to the house should be an "INLET" not an Outlet.. The power cord from the generator has a connector (MALE Plug) to connect to the generator, and a FEMALE to connect to the house mounted inlet. The inlet should be connected to a DEDICATED receptacle inside the house to allow use of an extension cord to power individual loads OR to a manual double pole double (SPDT) throw transfer switch if feeding the main service panel. Properly installed and listed SPDT transfer switch prevents connection of the generator to the utility. Alternates using UL listed circuit breaker interlocks are also available. Reliance makes a 6 circuit panel that includes an inlet, and six interlocked pairs of circuit breakers that facilitate power transfer. Do it correctly, use a licensed electrician.
Keep a flashlight in a handy spot and check the batteries regularly. Find space in the breaker box for a 240VAC two pole 60Amp breaker or higher. Run appropriate wiring that matches the breaker and more than the generator output to the outside and terminate into an appropriate 240VAC 60Amp outlet or bigger. Connect the output of the generator to the 60+Amp external outlet. Turn off the main circuit breaker from the utility feed to the distribution box. Turn off all the circuit breakers except one that has a running load. Start the generator. One at a time turn on the circuit breakers making sure they are loaded up before you go to the next circuit breaker. This should give you an idea as to how much of your house load the generator can handle. Before going back on utility power Unplug the generator. NEVER leave the generator plugged in for stand-by, and always turn off the 60+Amp circuit breaker when not in use. Unless you have an automatic transfer switch, the generator and the main breaker that interrupts the utility power supply must NEVER be connected to the load at the same time. If you want an automatic test start weekly you will need an automatic transfer switch. Also, if the generator is started by battery, you may also want to run a 120VAC outlet for a battery trickle charger to keep the battery charged for emergency and programmed test starts.
