Calling all Electrictians - Broken Generator, HELP!!!

[WillM]

Hello,

I'm in VA and just fired up the generator and was testing it out in advance of the hurricane. I was going to backfeed into my dryer's outlet after killing the main breaker and all but the necessary breakers (aquariums and fridge). The outlet is an older three prong 240V one. I have it wired correctly and plugged into the generator correctly, but I'm getting weird readings. I ran the ponytail into the basement from outside and the multimeter reads 208V between the two hot legs, a little low, but I should be OK with that I think, but the strange thing is between the neutral and one hot I get 24V and between the neutral and the other hot I get 24V. What the heck? I thought that each leg should be 120V. I also tested the generator output and it shows the same readings. Then after I unhooked everything and turning the breaker back on I tried the outlet in the house and it reads 240V between the two hots, and 120V between one hot and neutral and 120V between the other neutral and hot leg.

Any electricians know what could be going on?

Then part B, is this fixable before tomorrow evening or is this something I'll need to get another generator for?

Thanks in advance.

 

[jimmy frag]

you got a 208 volt reading between the two hots so all is well. for some strange reason the readings are obscured between the white and black. caused by you or the meter. the common is cancelling out the hot. most likely the white is not connected properly so you wont get a correct reading at 120. . you didnt tell us if the fridge and aquarium run fine while on the generator power

 

[jonmccullough]

It is possible the the 24v is an activation circut and will continue to read this way unloaded. To test this, kill main breaker, load a circut, then test the legs off the loaded breaker.

 

[WillM]

I was scared to flip the switch and power the house with the funny readings. Do you think it's safe to give it a shot?

I am scared that it will fry my fridge if it's not right.

I don't think it's the meter since the power from the outlet when I measure it with the breaker on is what I expect it should be (eg ~220V between the hots, and ~120V from each leg back to neutral). I don't think it's the pony-tail since it measures the same on at the generator outlet (eg ~208V between the hots, and ~24V from one leg to neutral) as it does in the basement....

Any other thoughts before I blow $2K on a generator before they sell out?

 

[jimmy frag]

one is cancelling out the other. give it a go.

 

[jonmccullough]

If the generator idles until demand is applied the 24v activates the gen power up. 208 + 24= 232. Its your stuff, your call, if it were mine I would flip this switch.

 

[jimmy frag]

do you own a lamp, a raidio ?

 

[WillM]

Yeah, I plugged a light in outside into the 120V outlet on the front of it and it works. I'm scared to plug it into my house power and potentially fry my stuff. I don't know a circuit that doesn't potentially have critical expensive stuff hooked into it. I went through with my GF earlier and tried each circuit breaker out and found just the ones that the aquariums and fridge are on. But again, I don't want to toast my auto top off or my LEDs. If the power goes out I'm sure I'll get desperate and try it out then. I'd like to know if I need to buy another one before they sell out and I'm scared to try it out without an electrician telling me it's OK.

I can unplug the critical stuff, but I have friends over to watch Dexter and can't do it right now. I'll do it later this evening on my basement circuit. I just hope nothing else is on that circuit I don't know about (just bought the house in June, so I don't know all the ins and outs yet).

Quandary.

 

[jimmy frag]

hello, hello, electrician here. construction maintenance licened since 92. you know back feeding the way you have has every circuit still protected right !

 

[WillM]

Sorry, sorry I appreciate your feedback! After Dexter goes off I'll give it a whirl and see how it goes. Thanks for your time and experience Jimmy!

 

[jimmy frag]

you,ll be fine. cheers

 

[staindsoul]

A three plug outlet in the house, how did you wire the plugs on both ends?

I'm not buying this activation voltage nonsense. Nor am I buying canceling each other out.

Edit:it sounds like you it is a floating nuetral generator. Yes it will be bonded when you backfeed the panel, but you better make sure you have wired it correctly.

FYI: 208volts is more than the allowable 5% nec voltage drop. So all is "not well".

 

[jimmy frag]

i believe he has a double ended cord with a 30 amp plug on each end, i dont buy the 24v thing but we dont know how he is measuring so its exceptable to me the reading is cancelling its self out. i thought the nuetral was not connected properly but he says it is and has tested with a lamp, dont know how because he has hooked up a 220v plug to it ? .

 

[staindsoul]

If he is wiring to a three prong plug, he ethier bonded the nuetral and ground at the generator or house, left the ground or left the nuetral.

Edit:he plugged a lamp into the front of the generator. Op how old is the generator, what brand and model?

 

[rickh]

Does your main panel have a lockout on the main breaker so you can't back feed into the power line?? Back feeding through a dryer outlet with 2 male plugs is asking for disaster. Also run that generator outside, not in the garage. R

 

[WillM]

The generator has a 4 prong outlet. The dryer outlet is 3 prong. I left the green wire (ground) capped on the dryer outlet side. I can ground the green to the house ground, but I tried that earlier and it didn't help. I tested between all possibilities of the wires on the basement side of the cable and the green didn't effect anything whether it was hooked up or not. Could that be my issue? I don't know if I can get an electrician out to my house tomorrow with everything else going on around here I'm probably not on the top of anyone's callback list. My dad helped me wire it and test it and he builds ham radios and is pretty electrically inclined, but is a dentist not an electrician.

 

[staindsoul]

the green ground is not the problem, i missed that you tested at the generator and got the same reading. IMO, the generator has a problem. From nuetral to hot you should be reading 120v not 24. What your readings at the generator on the 120v plug?

 

[WillM]

Does your main panel have a lockout on the main breaker so you can't back feed into the power line?? Back feeding through a dryer outlet with 2 male plugs is asking for disaster. Also run that generator outside, not in the garage. R

Yes, I can cut off the main breaker so it doesn't backfeed back into the grid, I don't want to toast my generator any worse than it already is or kill any line men. Also, the generator is outside in the back lawn not in my garage. Thanks for the common sense reminders

 

[WillM]

Hey Staind,
If I test between the two legs of the two prong 120V plug it tests at 24V. If I test between two left (or positive) legs of two separate outlets on the generator I get 208V, or two right (negative) legs again 208V. Nothing gives me 120V. I was worried this was going to mean a new generator in my immediate future (if I'm lucky and they haven't sold out).

 

[staindsoul]

Yep your generator has a issue. I bet that lamp didn't burn very bright, did it?

The generator, how old is it and what brand/model?