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Little off topic maybe, need help with generator and wiring

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Armourer

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#1
Try and make this as short as possible. I got a Lincoln 305D diesel welder/generator that I keep in my shop about 40' away from my house. We have been experiencing long power outages lately and have had to run it to power a little heater in the house (110v heater). I just strung some extension cords out and in through the window of the house to just get some heat inside. This got me thinking I need a better cord to run inside the house just to run a small heater and maybe a few other small electrical appliances. So I was wondering would it be better to use the 220V 4 wire plug off the welder, then convert it back to 110V inside the house (some how??) to reduce the amps that is drawn on the generator? Or does it even matter and just run the 110V plugs instead? What size of cord should be used for this length of run? Its a 10,000 watt generator. Thanks for the help.
 

Karl_T

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#2
How fancy do you want to get?

I put a disconnect between the meter and the load center. Then I plug in the generator to a 220 welder socket and have power to the whole house. keep the frig and freezer running, watch the boob tube, play on the computer, pump well water, power the gas stove and furnace, etc.

For one little 110 volt heater you are using less that 10% of that generator's capacity. A good 12 gauge extension cord would do it.
 

aliva

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#3
I would suggest that you take full advantage of your generators capacity 10000 watts should be around 40 amps witch would be a number 10 awg.
You can buy 3 conductor #10 SWO rubber coated wire, or go fancy and make it permanent and bury some wire underground to you house. If you go with the flexible wire install a 240v 40 amp twist lock plug on your house run the wire from the plug to 40amp double pole double throw switch. and then to a load center that contains just the circuits that you want to power up.
 

markba633csi

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#4
A 220 volt heater would be more efficient and would make better use of your (expensive) run of copper wire from the genset to the house
You should try to find out if the 220 volt outlet from the generator is actually two 110 volt circuits with a common neutral so you don't need to run unnecessary duplications of wire..
If you are lucky, you could run just 3 conductors to the house and have both 220 volts and 110, and with a 4 wire twist-lock outlet on your genset it may be that you have both voltages available from that single outlet. Get an ac voltmeter and check it out! :D
mark
 
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Bi11Hudson

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#5
I went a little overboard with my system. But then, I usually do everything electrical a little heavy handed. My generator distance is unknown, but by wire is around a hundred(100) feet. I have two residential buildings.(in an old neighborhood) One is the residence, the other is modified to be a shop. The metal shop in one side and wood shop in the other. Plus the various hobby shops in assorted corners.

The two buildings are on 50 foot lots. On the "shop" side, there is a barn some 60 feet behind the "little house" (Deep lots) The generator resides in that barn. There is a 100A submain from the barn to the shop. Welder and other heavy loads there. Then there is a 100A submain from the "big house" to the "little house". This feeds the shop, the metal working machines, wife's wood machines, my model trains, and the like. In essence, I have a submain feeding another submain. All are four(4) wire circuits, a legal requirement in my area. Neutral and ground as seperate conductors. Read http://www.hudsontelcom.com/ A little down the page is "Home Shop Electrics", an extensive (50+ ppg PDF) writing on the subject. Most of it won't apply in this instance, but should provide some insight to the subject.

For basic operation, with a 6.5KW genset(6500 watts) to back feed into the big house, there are numerous circuit breakers between the incomming line and my genset. The established protocol for dealing with an extended power outage is to (1): Trip the main breaker on the incomming line. (2): Verify main breaker is off. (3): Open the breaker to the shop (4): THEN proceed to the barn and start the generator. All of this is to assure, absolutely, that the generator will not backfeed into the pole pig in the alley. That might be my buddy on the pole down the street.

Once this is complete, then return to the house. Once again assure the main breaker is off. (functionally the same as pulling the meter) Then, and only then, close the breaker to the shop. This allows a backfeed to the main panel.

My wiring is marginal for 100 Amp service. But all breakers in this circuit are rated at 75 Amp, 2 pole. We don't use air conditioning. The furnace is gas, with a millivolt valve. As in, no connection to the electrical system. All other electrical loads have been run together and there was no interruption. The only combination that I haven't tried is the kitchen range, along with the dryer, and trying the welder. That combination is unlikely to occur.

The wiring is mostly copper, #2 AWG SER, with one aerial span of #2 Aluminium "tri-plex". Everything is set up as I would have connected an addition on an industrial building. The one difference is that instead of using crimp on barrels (cigars), I used kearneys (split bolts), which I prefer. Experience there. The Al to Cu connections were well greased with the appropriate grease.

Again, I admit to being heavy handed. But this system has been in place for over twenty (20) years. There have never been any overloads, or complaints from the local power company. As far as recommending for your system, I won't. Not without walking over it and seeing it in person. But good judgement and willing to pay a few dollars more for the correct parts will yeild a solid system

Bill Hudson​
 

Cadillac

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#6
I have a 10,000 watt gen/welder in my shed about 40’ away. I made a plug for the 220 lines on panel of gen. Used 3wire #10 cord with a 50amp plug that plugs “back feeds” into my garage.
Power has only gone out once in eight years. Throw the main breaker in-panel start the generator and let their be power. You MUST make sure you throw the main and turn off generator before resetting main breaker when power comes back. I was able to run all the fundamentals. Except the shop:(
 

zuhnc

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#7
Back-feeding is NOT LEGAL. You will kill yourself, a loved one, or a lineman. Get a proper manual or automatic transfer switch. 'Nuff said. zuhnc
 

Blackjackjacques

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#8
Try and make this as short as possible. I got a Lincoln 305D diesel welder/generator that I keep in my shop about 40' away from my house. We have been experiencing long power outages lately and have had to run it to power a little heater in the house (110v heater). I just strung some extension cords out and in through the window of the house to just get some heat inside. This got me thinking I need a better cord to run inside the house just to run a small heater and maybe a few other small electrical appliances. So I was wondering would it be better to use the 220V 4 wire plug off the welder, then convert it back to 110V inside the house (some how??) to reduce the amps that is drawn on the generator? Or does it even matter and just run the 110V plugs instead? What size of cord should be used for this length of run? Its a 10,000 watt generator. Thanks for the help.

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.
 

Blackjackjacques

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#9
Back-feeding is NOT LEGAL. You will kill yourself, a loved one, or a lineman. Get a proper manual or automatic transfer switch. 'Nuff said. zuhnc
Backfeeding is not illegal the last I looked and the NEC is silent.
 

Logan 400

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#10
I'm not saying do or don't but I will say that proper overcurrent protection must be followed and a minimum of a breaker lock off should be installed on the main breaker to avoid back feeding to service provider.
 

tq60

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#11
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
 

tq60

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#12
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
 

hermetic

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#13
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!
 

Downunder Bob

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#14
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.
 

zuhnc

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#15
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
 

aliva

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#16
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
 

zuhnc

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#17
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
 

aliva

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#18
reliance-controls-power-inlets-pb50-64_1000.jpg reliance-controls-power-inlets-pb50-64_1000.jpg More 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
 

zuhnc

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#19
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
 

aliva

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#20
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
 
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