| One electrical problem leads to another. [message #96762] |
Sun, 22 August 2010 07:43  |
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RF_Burns
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma:
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Senior Member |
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Yesterday I decided to change the long clumsy 50Amp cord to a more manageable 4ft cord and make the existing cord into a 50Amp extension cord. I had bought a 4ft stove power cord for the job.
I removed the old cord and while hooking up the new cord I noticed the ground wires inside the breaker panel were almost touching one of the line lugs (couple thicknesses of paper clearance). Its a wonder the vibration driving down the road with the Generator going for the AC, didn't cause a short.
A PO had replaced the generator socket with a surface mount receptacle that was hard to get at so I decided to install a surface mount. When I removed the surface mount receptacle, the connecting wires to it came out too! There were 2 wire and 2 black wires about 8" long that had been crimped connected down inside the flex conduit. There was no way I could work though the receptacle hole in the side of the exterior electrical compartment so I removed the access cover behind the breaker panel and all the wiring that goes with it.
After removing the box from the BX type cable, the two wires would only come out about 1" beyond the conduit. Geez! how cheap can you get with wire!... another 6 or 8" please! and both are Black wires so now I have to figure out which is hot and which is neutral/ground. I also checked to see if I could cut back the flex conduit to expose more wire, but there was barely enough as it was.
So I look at pulling new wires though the flex conduit. With all the tight bends I knew that would be a major and near impossible job with heavy cables. So I elected to fix it as it was, crimp these short pieces back on, solder and heat-shrink them. But now I have figure out which wire is which. They are too short to separate and start the genny, so I measure resistance to ground and find one is 0 ohms and the other is 7ohms.. Ok the 0 ohm wire has to be the neutral/ground. I crimp the wires back on and double shrink tube them.
Paula strugled to hold the box in place from the outside while I tried to get the socked mounted in the electric compartment from the ouside.. after alot of cussing I got it back in. Started the genny and tested the voltage at the new socket.. all looks good so I plug in the new short cord and the generator feels a bit of load.. Hmm I think.. I was sure the AC was off.. maybe the water heater is ON. Then I hear the load come off the genny. Inside there is no power, unplug and check at the genny socket, no power.... pull open the Onan and I see the breaker is tripped.
I reset the breaker and power is back at the socket... so I check for voltage between the body and ground... Damn.. I have the Hot and Neutral reversed! So I shut down the genny again and remeasure my resistances to ground... same what I assumed was neutral/Ground has 0 ohms and what I figured was Hot is 7ohms. But I obviously have them reversed! How can the neutral/Ground which is grounded directly read 7 ohms while the Hot which goes through the reactor and armature coils read 0!
Well I can't redo the splices at the socket end to keep the proper colour code, but wait... both power wires at the Onan are White!! Who wired this thing!! there is a junction box at the back of the Onan box where the two White wires from the Onan join the 2 black wires going to the socket... it would be nice if would have used a Black (Hot) and White Neutral all the way though.
I wanted to ohmmeter both wires from the Onan right through to the socket to be sure they were isolated and one was not grounded in that junction box so I opened both connections. The neutral is just 2 lugs bolted together and taped. They appear to be isolated.
I had no other choice short of pulling out the cabinets etc, to reverse my wiring at the new socket. I used a permanent marker to write a warning to the next guy about the reversed wire colours. So after more cussing to get the socket back in the box its now back together again and ready for a test.... BUT.... when I opened that neutral connection at the back of the Onan, the small #10 bolt dropped from by greasy fingers. I can't find it anywhere so I have to assume it fell through the plastic covers at the back of the genny and inside. I'm afraid to start the Onan until I find this little bolt as it might damage the generator itself... so back to that today.
I really hope I don't have to pull the Onan out to find that little screw as it doesn't look like a fun job.
And so another little GMC job becomes another BIG GMC job!
The saga contines......
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
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