Portable Generator Smokes Office Epuipment

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davet

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Power Co.shut down bldg. owner gets 8kw gen.and disconnects feeders to 1phase/3wire 240v. cb panel.Hooks up a spliced cord from gen. to cb panel .Powers up gen.smokes 2 computors and 2 printers.I found that the wired plug was wired 2hots and neutral,no ground,and pluged into the gen,plug of ( 4wire/120v.-240v. ).( the neutral plug prong was properly connected to the neutral slot of the gen.plug ).During operation the spliced cord due to poor splice lost 1 hot leg which resulted in the other leg to jump up to 240v. to neutral, frying the office equip.The gen.plug brkr.did not trip.
Q. Can anyone explain why this happend? and how to prevent this.Is this an inherent gen.design that allows this to happen? or a wiring problem?
Please advise.
 
It doesnt sound like you lost a leg, it sounds like you lost your neutral at a splice and everything went 240 by backfeeding through whatever was plugged in, and it traveled on the neutral conductor between devices, but wasnt able to go back to the source (generator)
 
davet said:
Power Co.shut down bldg. owner gets 8kw gen.and disconnects feeders to 1phase/3wire 240v. cb panel.Hooks up a spliced cord from gen. to cb panel .Powers up gen.smokes 2 computors and 2 printers.I found that the wired plug was wired 2hots and neutral,no ground,and pluged into the gen,plug of ( 4wire/120v.-240v. ).( the neutral plug prong was properly connected to the neutral slot of the gen.plug ).During operation the spliced cord due to poor splice lost 1 hot leg which resulted in the other leg to jump up to 240v. to neutral, frying the office equip.The gen.plug brkr.did not trip.
Q. Can anyone explain why this happend? and how to prevent this.Is this an inherent gen.design that allows this to happen? or a wiring problem?
Please advise.
Click to expand...

davet, You say 1phase/3wire 240v. cb panel.

Is this a panel with no neutral, or no egc, or only 120v jumped to both phase busses. Some

UPS systems only deliver 120vac.
 
Gen.Smokes Office Equipm.

Gen.Smokes Office Equipm.

No egc back to gen.
I agree with ultramegabob,who gave a resonable explanation as to how this occurred.
Q.Would running a seperate grnd.wire back to gen.plug help?
Thank you all for your input.
 
the grounded conductor does nothing for the function of the circuitry, it is for bonding the metal case of the generator to the system ground, after reading the original post again, I believe you are using a spliced cord for your connection, this is a violation, and most likely the source of your problem. make a new 4 wire cord and run 4 wire all the way to the panel.
 
davet said:
Power Co.shut down bldg. owner gets 8kw gen.and disconnects feeders to 1phase/3wire 240v. cb panel.Hooks up a spliced cord from gen. to cb panel .Powers up gen.smokes 2 computors and 2 printers.I found that the wired plug was wired 2hots and neutral,no ground,and pluged into the gen,plug of ( 4wire/120v.-240v. ).( the neutral plug prong was properly connected to the neutral slot of the gen.plug ).During operation the spliced cord due to poor splice lost 1 hot leg which resulted in the other leg to jump up to 240v. to neutral, frying the office equip.The gen.plug brkr.did not trip.
Q. Can anyone explain why this happend? and how to prevent this.Is this an inherent gen.design that allows this to happen? or a wiring problem?
Please advise.
Click to expand...

dave after you complete the investigation please get back to the post I'd be very curious ps: I too agree if you lost the neutral you'd have a problem but perhaps you need 4 wires hot hot neutral and ground to "stabilize the voltage to ground"
 
Gen.Smokes office Equipm.

Gen.Smokes office Equipm.

After reading additional posts,I replaced the 3wire cord that the owner installed with a 4 wire.Since grnd.wire and neutral wire would terminate on the neutral bar,loosing the neutral wire or the grnd wire,I believe I would still maintain a neutral connection ( or would I? ).
At any rate,I corrected this violation.
Thanks for all your input.
 
Dave,

I would also check the idle speed on the genset, it may be too high or low and it may have caused an under/over voltage situation that the computers did not like. They can be sensitive to the power feed voltages. Keep us posted
 
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