Little off topic maybe, need help with generator and wiring

Most folks who use a portable generator to feed a home:
1. Engage the main disconnects to isolate the generator from the utility should the utility service come back
2.Connect the generator to the dryer 4-wire receptacle circuit and feed the whole house
3. Manually trip off less important loads

This way you have both 240 & 120V. If you have a well pump - odds are it is 240V and you would want that as a priority load. But wiring for 240 gives you both 240 & 120V

What I did was wire in a 4 wire generator receptacle rated for wet space/outdoors in parallel with dryer receptacle but located the generator recep outdoors in the vicinity of the generator. My port gen is 7.5 kW and use 10 awg flex service to feed the dryer's 30A circuit breaker. This arrangement is my "Temporary Emergency Backup" in case my fixed 50 kVA diesel gen is down.

The size of the cable you need between the gen and the receptacle will be driven by the diesel gen breaker rating. If its 40A, then you should be using 8 AWG. Technically, if the dryer circuit is fed from a 30A breaker, you could argue to use the 30A cable. You may find it difficult to get flex service 8 AWG cable that will fit into the standard gen receptacles.
Let's hope there is a proper switch in there.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
We see this all over the place.

Killer cheater cords and other creative things that can kill folks.

Transfer switches are cheap.

One real cheap version is a simple set of interlocked breakers where it one or other can be on.

Generator on ONE and line on other and they connect either source to panel.

These types of things must be idiot proof in that no way can a line be hot from Benny.

Too easy to forget to turn off something when doing it otherwise

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
there are two very simple and safe ways to do this, and they are the methods that have been in use as long as standby generators have existed. the fully automatic system uses a contactor held closed by the mains power, when the mains power fails, the contactor breaks the connection to the incoming power, and starts the generator, when the generator is up to speed and at full output the load is switched on to the generator by the generators output relay. The manual system is exactly the same, but uses an all pole disconnect switch which is used to switch the load from incoming supply to generator, and then to manually start the generator. In each case there is no possibility of back feeding into the mains. problems occur when people try to feed into their house or shop wiring without disconnecting the mains, and you cannot beat or legislate against stupid!
 
Here in Australia it is illegal to connect a secondary (portable genset) to a domestic service unless an approved isolating switch is installed by a licensed electrician.

I have such an installation, its a simple 3 way aux. switch with center as off. Switch up is input1 = mains, and down is input 2 = genset. The genset 6.5KVA is permanently wired in.

So when mains power fails. start genset, switch aux switch from position 1 to position 2 and selected circuits are live with no possibility of back feeding to mains when mains power is again available simply throw switch from 2 back to 1 and stop genset. works very well.
 
Good suggestions for the manual or automatic transfer switch. With the welding machine output, the manual switch is the way to go. Wire it to provide for critical loads only; don't have to switch the whole house. Manual switches are cheap compared to a lawsuit or insurance denying payment for doing something stupid. The "cheater" cords are also called "suicide cords", for good reason. With a manual switch, "even a caveman" could power up the circuits. Your spouse, child, neighbor, will not know or remember to open the main breaker. Again, GET A PROPER TRANSFER SWITCH. zuhnc
 
Just to clarify ,In my post I said to connect the generator to a double pole double throw switch which is essential an manual transfer switch, no way can the generator ever connect to the main power infeed
 
My comments are directed at those who think that a male double-ended cord plugged into the dryer or stove outlet is acceptable. Those of you who have a proper transfer switch, of which a DPDT switch is one, kudos to you. I, myself, use a manual switch with INTERLOCKED breakers from the main panel and generator. Can't have both sources connected to the load simultaneously. Numerous types of this equipment out there, inexpensive, and easily installed. Some allow individual circuits to be powered from the generator; others, like mine, require all your critical loads to be either one power source or the other. Top priority is to be safe, and not jeopardize either yourself or others, with inappropriate equipment usage. zuhnc
 
reliance-controls-power-inlets-pb50-64_1000.jpgreliance-controls-power-inlets-pb50-64_1000.jpgMore clarification, When I posted to use a cord to connect the generator to the house via a twist lok plugs I should have made it clearer. I agree that a double male cord is un acceptable. My installation uses a male plug at one end to connect to the generator and a female to connect to the house, along with the DPDT switch there is absolutely no hazard of electrocution. My mistake for not being more specific. Also this would be installed in an approve weather tight enclosure
 
I agree; the correct way of doing things. No danger, and anyone can start the generator, connect up, throw the switch, and LIGHTS! Nothing to forget or remember. Very elegant and simple. A lot of small (6-10 circuit) manual switches have the same type of power inlet. Connect the generator with the proper cord, throw the circuit switches to "generator", and you are in business. Aliva - do you switch the whole house or just select circuits on a subpanel? I have my 4kw on a subpanel for select circuits. I don't need 240 for anything. I have a 240 oven, which I don't need when the power is out, but the stove is gas and heating system is gas fired hydronic (radiators). zuhnc
 
I use a sub panel, unfortunately I only have a 3kw genset so I'm limited on what I can power up, NG Furnace freezer and 2 refrigerator's. even then I have to be selective . In the summer my main concern is the freezer and refrigerators, winter, the furnace is the primary circuit .Don't need a freezer in winter I have one outside in the outdoors. Summers the opposite no need for heating
 
Back
Top