Emergency generator question for you electricians

[dstig1]

If it's 8000 W, at 240V, that means it puts out max of 8000/240=33.3A. That's just over 10ga, so 8 ga should be plenty big at that distance...but...I'd do what Boggen suggested and install a hardwired outlet near where the gen would sit. Far easier in the long run. You also need a proper generator cutover switch for safety so you don't back-feed the main power lines and kill a lineman. *** If none of this makes sense to you, then you really need to hire a licensed electircian. While it may not be too horribly complex, the consequences of a mistake can be quite severe - fire/injury/death.

 

[HCJtractor]

If it's 8000 W, at 240V, that means it puts out max of 8000/240=33.3A. That's just over 10ga, so 8 ga should be plenty big at that distance...but...I'd do what Boggen suggested and install a hardwired outlet near where the gen would sit. Far easier in the long run. You also need a proper generator cutover switch for safety so you don't back-feed the main power lines and kill a lineman. *** If none of this makes sense to you, then you really need to hire a licensed electircian. While it may not be too horribly complex, the consequences of a mistake can be quite severe - fire/injury/death.

I already have my panel wired with a transfer switch, with a receptacle to plug up a generator to. I have used an 8000 W many times in the past (but it was stolen) so I am simply replacing it. Just thought since I had to spend $1500 to get a comparable one, I may justify getting a welder/generator. I need something to run my Miller 211, and often need a stick welder at the farm where there is no power. I originally was considering a Miller Wildcat 200 that is a little more portable, but in researching it, it just doesn't have the power to run my Mig or a 1/2" capable plasma which is next on my tool list. I was planning mounting the Bobcat on a small trailer so that I can manage it, and take it to the farm when needed, weld with it in a warehouse where my shop is (and store it there), but have it available for the rare power outage at my home in the city (also I can justify this purchase to my wife as simply replacing my stolen generator) If the power goes out for more than a few hours, I can run to my warehouse, pick up the Bobcat, and hook it up to the transfer switch I already have. I live in S.C. so the storms are not too bad or that frequent. In the last 15 years, I only had the need for a generator 3 or 4 times, the longest for a week, but that was very uncommon.
So using an extension cord would not be that big a deal. Hardwiring it certainly is neater and I may do that later, but in the meantime, thought a cord would be simpler. THanks for the replies.

 

[Baby Grand]

Jim, you may have less success with the second muffler than you hoped. I added a car muffler on a stand to my 5000 watt Honda.

It muffled the exhaust note more, to be sure, but the noise inside the garage (I had an exhaust port cut through the door panel) was pretty much the same. Most of the noise from the air-cooled Honda was mechanical, much more so than I thought originally.

Sean

+1 Did something similar on a Coleman generator and it still has lots of noise radiated off the engine block.

Dang. It seemed like such an easy solution. I should have known.

 

[HCJtractor]

60 feet of cord sounds rather long and cumbersome.

why not look at installing a cable underground out to garage or were ever. with a receptacle. that you then could use a short (cord) between gen and receptacle?

After reading your advice, I re-thought this. I could run cable from my panel which is on one side of my home, through the basement/crawlspace, to my carport which is on the other side, then add a receptacle (transfer) there as you suggest. I could park the trailer there and connect (carport is open so fumes not a problem) Still use #6 cable? That does seem easier than using a long extension (and cheaper)

 

[Chilly807]

After reading your advice, I re-thought this. I could run cable from my panel which is on one side of my home, through the basement/crawlspace, to my carport which is on the other side, then add a receptacle (transfer) there as you suggest. I could park the trailer there and connect (carport is open so fumes not a problem) Still use #6 cable? That does seem easier than using a long extension (and cheaper)

Generally speaking, the hard cable itself SHOULD be cheaper than the SJTW cord you'd need for a flexible extension. If you're going to go that way, I'd suggest rodent-proofing the run by using armored BX style cable. The size depends on how many amps you want to run through it, I'm no expert on that.

The biggest SJTW cord I've seen readily available in Home Depot, for example, is 10/4. I'm sure bigger stuff can be had, but may be special order, might even have to buy a spool of it.. the 10/4 is pricey as it is, I think it was $5.80 CDN per metre the last time I bought some.

We have a typical transfer switch set-up, one that breaks ALL the connectors going back to the utility, even the common. There's an outside plug-in for the generator, a recessed male plug. It's illegal here to back-feed through a dryer, range, or welder receptacle.

Our transfer switch feeds a generator panel which in turn feeds selected circuits in the house. The switch disconnects the generator panel from the main utility feed before it makes the connection to the generator, so you can't have two supplies actively feeding the house at the same time. A 30 amp connection runs between the main panel and the generator panel to provide power under normal circumstances. I'll take some pics tonight if I remember.

Having the generator feeding the whole house via the regular breaker panel is a problem, because the common wire is often still connected to the utility even when the main breaker is open. As someone mentioned, if you have a problem you can back-feed 220V through the common wire up to the transformer, and then you have serious voltage available to injure or kill someone working on the lines nearby. That's my understanding of it anyway, if I'm wrong someone will point it out.

Sean

 

[dstig1]

You don't need #6 for that as 8 is fine. You can use 6 if you like, of course. If you hard wire a closer outlet, your best bet may be getting a stove replacement cord/plug from a home center and cutting off the ends to rewire as needed. You should be able to find an 8 ga in that easy enough, but 6 will be tough. Those cords tend to only be up to 7' or so long, which may be too short for you. Otherwise any electrical distributor will cut to length whatever flex you need (at least here they will).

Sounds like you are setup for a gen just fine, from the previous set up transfer switch, etc. The closer outlet will make life a lot easier, methinks.

Edit: seeing the posts below, if it has a 50A breaker, then you probably do need 6 ga, but it does not seem likely to me to have a 50A breaker on an 8000 w gen. I would expect to see 40A. But whatever it is, that's your guide.

 

[grsthegreat]

Generally speaking, the hard cable itself SHOULD be cheaper than the SJTW cord you'd need for a flexible extension. If you're going to go that way, I'd suggest rodent-proofing the run by using armored BX style cable. The size depends on how many amps you want to run through it, I'm no expert on that.

The biggest SJTW cord I've seen readily available in Home Depot, for example, is 10/4. I'm sure bigger stuff can be had, but may be special order, might even have to buy a spool of it.. the 10/4 is pricey as it is, I think it was $5.80 CDN per metre the last time I bought some.

We have a typical transfer switch set-up, one that breaks ALL the connectors going back to the utility, even the common. There's an outside plug-in for the generator, a recessed male plug. It's illegal here to back-feed through a dryer, range, or welder receptacle.

Our transfer switch feeds a generator panel which in turn feeds selected circuits in the house. The switch disconnects the generator panel from the main utility feed before it makes the connection to the generator, so you can't have two supplies actively feeding the house at the same time. A 30 amp connection runs between the main panel and the generator panel to provide power under normal circumstances. I'll take some pics tonight if I remember.

Having the generator feeding the whole house via the regular breaker panel is a problem, because the common wire is often still connected to the utility even when the main breaker is open. As someone mentioned, if you have a problem you can back-feed 220V through the common wire up to the transformer, and then you have serious voltage available to injure or kill someone working on the lines nearby. That's my understanding of it anyway, if I'm wrong someone will point it out.

Sean

your correct about the feedback issue. almost all panels can be retrofitted with a generator bypass, and these were all legal thru the 2008 code book. I have no idea if this has changed with the new 2011 codes that come into effect in a few months.

What i generally do with my gen panel installs, is to install a new, 60 amp (or 30 amp) subpanel next to the main panel and move all circuits i want on my generator (whatever the generator can handle) to the new panel, then i add a generator supply breaker with built in bypass from utility power.

this makes it alot easier to isolate what can and cannot run off the generator. All you do is start up the generator and flip 1 switch.

very straight froward and safe for the lineman.

I have a 10KW propane generator on my house, and its used alot in the winters here in N. Idaho. I can start my generator from inside my house. I HATE automatic switchover units for one reason. If no one is home, i DONT want my generator running. $$$$$


I have hooked up a few gen/welder units to house panels. The suggestion of underground to within a few feet of the gen location is what ive done in the past. Flex cord is mucho expensive. pipe and THHN wire way cheeper..then again, copper is about $5.00 a pound now with scrap copper bringing in $3.60 here.

 

[k8m]

crazyal is correct per the NEC the wire size is determined by the overcurrent device

 

[HCJtractor]

First thing I would say is you can't use how much you think you will draw for power to judge what size wire you need. The generator should have a breaker, that's what you need to size the wire too.

I think the breaker is 50 amp

 

[varmint]

All the feedback on wire size, transfer panels and outlets agrees with what I had learned in installing my transfer panel. One more thought is this: marina shore power receptacles, cords and such are ideal for generator use- the recessed male recept. are weatherproof and well made, and if you can afford them, the power cords are perfect. Once you get all this stuff, you won't need it. Well, maybe not.