Generator Question

[gerard]

I don't understand the "separate ground from the grid" ground? Your neutral bars just go outside the house onto your ground rod which then goes into the ground. You (or at least I) don't have an actual neutral that goes from your box back to the pole. Guess if you're close enough to a ground strike from lightning you're going to lose some things anyway. Guess I'd rather risk it and have the convenience of not having to run cords all over the place. (Or were you saying by running directly to the appliance you totally isolate everything from the grid? That would make sense but I'll still go for the convenience /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[Mrwurm]

Gerard, I'm glad you brought this up. I thought I was crazy and I did'nt want to mention it. I believe I only have two hot wires coming to my house also. My ground and neutral both are attached to a rod that was pounded in the ground. So, in this case, maybe the main breaker does provide an effective disconnect from the main?

Jerry

 

[gerard]

The main breaker will disconnect you from the grid but not from the actual ground in the event a lightening strike hits right near your house but I wouldn't worry about that. If he really wants to be safe when running a generator he would run a separate ground from the generator, then he would be back in the same boat, being exposed to a lightening strike. (You'll notice a separate ground wire from the generator that you're supposed to run directly to a ground, otherwise if you were out with the generator running, it was raining, you touched the wrong part of the generator, YOU could be come the ground and get a nasty wake up. I don't know too many people who ground the generator separately, most just rely on the house ground if backfeeding. Bottom line is you can't protect yourself from every situation. Guess you house itself could get struck by lightening and the generator would be the least of my worries in that case!!! /forums/images/graemlins/shocked.gif

 

[RET]

Gotta jump in with some more questions...
I just got a new gen. yesterday - Yamaha YG6600DE. Cool unit. You don't put oil in the engine....it shipped with a free gallon of 100% pure testosterone!
I had to beg the boss to let me spend the $$ on it, so I'm SOL in getting more $$ to get a proper transfer switch and associated wiring installed this year.
So, I'm going to have to use the extension cord method - at least for the next year or so.
My gen. has only one 20A 'standard' GFCI outlet; otherwise it has one 120V 20A twistlock RV outlet, one 120V 30A RV outlet, and one 120/240 30A RV outlet.
I want to be able to use at least a couple of these RV outlets so I can utilize the unit's full power capability, so I plan to purchase the proper RV twist locks, some long length of good quality extension cord (12 ga. min.) and supplies to build standard plug-ins for the other end of the cords. Is that OK? Does Home-Depot / Lowe's carry these twist lock RV type oultets or do I need to visit an RV dealer?
thx,
RET

 

[MJB]

Home Depot carries all the common types of twistlock plugs and receptacles, as well as various sizes of SO cord to make up your own extensions. Get a tight grip on your wallet though, some of those connectors are expensive. /forums/images/graemlins/shocked.gif

 

[gerard]

Not sure what you mean by a 120/240 volt outlet? If it has 4 prongs and if you hook up all the wires (two hot a neutral, and a ground) it will be 240 volts. Maybe an rv is set up to take this in as 240 but splits it at a junction box so two legs have 120 volts each? Re getting the plugs an electrical supply house is probably a better bet and will have all the nema plugs. Do you have a 240 volt circuit accesible to the generator now? If so you can backfeed the panel and power your whole house though there are more safety issues that way if you don't know what your're doing. I've talked to linemen about backfeeding the line issue. All have said even when the line is down it's treated as hot. When they work on the lines (and they often work on hot lines that are carrying 4800 volts, not just 240) they make sure they aren't grounded so they wouldn't get shocked anyway. (Same reason a bird can land on a 13000 volt line. Just don't throw it a wire that hangs to the ground!!). It's a pretty simple set up and gives you a welding circuit if you ever decide to weld.

 

[RET]

Evidently, as you theorized, the 120/240 outlet IS intended for RV setup's that can split it downstream - and it is a 4 prong outlet. The operating manual even shows which legs to use for 120 and which combination gives you 240. I'm not going to fool with this one for a while. If I can rig up to use the two 120V twist locks, that will do fine until I get a transfer switch installed later...I don't plan to tie into my house wiring until I can do it right...will just make-do with extension cords. Utilizing all three 120V circuits on the gen. gives me two 20A circuits and one 30A circuit....that's somewhere north of 8000 watts theoretically available.....and Gen is only rated for 6600 max.
New question - a 240V circuit is simply two 120v lines...but each leg is 180 deg out of phase with the other. right?
thx!
RET

 

[Anonymous Poster]

NO, they are in phase. It looks like this
120v ---- neutral ----- 120 volts
^ ----------240 volts------^

 

[RET]

Franz,
Thanks. I keep asking stupid questions 'cause I'm convinced that one day I might gain a little wisdom. I've figured out that the best way to learn is to be completely honest about your stupity....and folks will gladly teach you anything you want to know.
I stopped by Home Depot this evening and picked up a couple of those 120V twist locks. Then, I went down the aisle a little way hoping to get some 10/3 SJ cable.....but the salesman told me they only stock 12 guage max. He told me that 10 guage is considered 'commercial' and that they could not carry it due to some 'agreements' - Home Depot can only carry supplies for 'residential use'. Nice guy. he told me exactly what I should get. He gave me the names of some local electrical supply folks in the area - I'll visit them in the morning.
Thanks for teaching this dumb country boy! /forums/images/graemlins/tongue.gif
RET

 

[Anonymous Poster]

It ain't stupid to ask questions about something you don't know. Stupid is when you don't know and refuse to ask.
Stupid is also runnin over a gator on the road, and then walkin back to see if he's hurt, and gettin close to the front end of the gator. That definitely has to be the textbook definition of stupid.