Forensic Analysis of Electrician Screwup

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JamesBonded

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I'm hoping someone on this forum can give me some insight into what exactly happened during a recent screwup by an electrician I have working for me. The situation is as follows - I recently had an electrician install a regular 120V 1P duplex outlet in a large room in the basement of a new building that is in the construction phase. The building has a 120/208 3P service. When he was wiring the outlet, he had run out of white conductor for the neutral, so he used a red conductor instead, but wrapped it in white electrical tape at the outlet. He also used a red conductor for the hot leg. Unfortunately, his assistant who was connecting the outlet to the circuit back at the panel didn't get the memo, and connected the first red wire to a single phase circuit and connected the other red wire (not wrapped in white tape at the panel, only at the outlet) to another circuit on the same phase as the first red conductor. So, fast forward an hour and we go to plug in a simple 120V dehumidifier to the outlet. The dehumidifier runs initially, but then burns out after about 30min of operation. So, my question is this - Did the dehumidifier burn out because this wiring configuration (2 red conductors and a ground) brought 208V to the dehumidifier or 240V to the dehumidifier? If someone has any insight into what actually happened here, I'd love to know.
 
If the service is 208Y/120 and there are no step-up transformers then the applied voltage due to the wiring error was 208 volts. I'm surprised the unit lasted that long.

Welcome to the Forum. :)
 
The error by the assistant aside, I do not believe that the code allows what was done, namely using white tape to indicate that a non-neutral color wire is in fact a neutral.
In a cable perhaps, but not when individual wires are pulled in raceway.
 
JamesBonded said:
I'm hoping someone on this forum can give me some insight into what exactly happened during a recent screwup by an electrician I have working for me. The situation is as follows - I recently had an electrician install a regular 120V 1P duplex outlet in a large room in the basement of a new building that is in the construction phase. The building has a 120/208 3P service. When he was wiring the outlet, he had run out of white conductor for the neutral, so he used a red conductor instead, but wrapped it in white electrical tape at the outlet. He also used a red conductor for the hot leg. Unfortunately, his assistant who was connecting the outlet to the circuit back at the panel didn't get the memo, and connected the first red wire to a single phase circuit and connected the other red wire (not wrapped in white tape at the panel, only at the outlet) to another circuit on the same phase as the first red conductor. So, fast forward an hour and we go to plug in a simple 120V dehumidifier to the outlet. The dehumidifier runs initially, but then burns out after about 30min of operation. So, my question is this - Did the dehumidifier burn out because this wiring configuration (2 red conductors and a ground) brought 208V to the dehumidifier or 240V to the dehumidifier? If someone has any insight into what actually happened here, I'd love to know.
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Welcome to the forum. If both wires were connected to the same phase, there would be 0V potential at the receptacle, and the dehumidifier wouldnt run at all. 208V would be present between any 2 phases of a 120/208Y service and fry 120V equipment, usually much faster than 30 minutes (like a few seconds). 240V would only be present in a split phase, high leg, or 240V delta service.
 
Must not have had smoke detectors or you would have known about it in under a minute.
 
JFletcher said:
Welcome to the forum. If both wires were connected to the same phase, there would be 0V potential at the receptacle, and the dehumidifier wouldn't run at all..
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only if they really are on the same phase. i'm betting a cheeseburger
that if you measured, you'd get 208 between them.

as described, you'd have 120 volts to ground from hot to ground.
that won't burn anything out, and 0 volts hot to neutral, and that
won't burn anything out.
 
ptonsparky said:
Hindsight...the sacrificial $15 GFCI that most likely should have been there during the construction phase would have been a lot cheaper than the dehumidifier.
Click to expand...

I'm more concerned about what happened to the building than the dehumidifier.

OP: Is the building ok?

Edit: I went back and read post #1. Seems the only loss was the dehumidifier and maybe some ego.
 
From what I read you state the receptacle was put in for temp power -- to clarify is the humidifier being used during the construction? had no one else use the receptacle for construction drilling, or drop lights? The circuit described shall not be part of permanent power. Should have been gfci & would have had issues if there was 208 v between phases -- agree the would be no potential difference if in fact was on the same phase -- I inspect temp power when installed on jobs & usually look at the panel makeup so having a 240v 20a line would be unusual as most 240v line would be 30 -50 amp. I getting the feeling an unqualified got into the box without electrician's knowledge - just an opinion.
 
I'd say very likely the red wires were landed on different phases and that delivered 208V to the dehumidifier.

The dehumidifier probably has a small impedance protected motor. With a small motor like that, I could see it lasting 30 min. before it quit, and I could see it burning out without any major fireworks.

There may also be some type of overload in the dehumidifier that burnt out. It might be a fairly easy to fix it.
 
steve66 said:
I'd say very likely the red wires were landed on different phases and that delivered 208V to the dehumidifier.

The dehumidifier probably has a small impedance protected motor. With a small motor like that, I could see it lasting 30 min. before it quit, and I could see it burning out without any major fireworks.

There may also be some type of overload in the dehumidifier that burnt out. It might be a fairly easy to fix it.
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I believe you describe a humidifier. Dehumidifiers have a small refrigeration unit. Not so easy to fix.
 
ptonsparky said:
Hindsight...the sacrificial $15 GFCI that most likely should have been there during the construction phase would have been a lot cheaper than the dehumidifier.
Click to expand...

Kind of makes you wonder about this whole deal doesn't it?

Either the electrical inspector or OSHA could have written them up for a safety violation.

I would be more worried about a safety violation than the code violation.

I also wonder why the electrician was letting his assistant do the termination in the panel and not checking things out or even doing any sort of test of the receptacle. Why wouldn't he use a GFCI protected receptacle?
 
JFletcher said:
Welcome to the forum. If both wires were connected to the same phase, there would be 0V potential at the receptacle, and the dehumidifier wouldnt run at all. 208V would be present between any 2 phases of a 120/208Y service and fry 120V equipment, usually much faster than 30 minutes (like a few seconds). 240V would only be present in a split phase, high leg, or 240V delta service.
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Since the thread title says Forensic analysis, I am with you here. Assuming we are trying to get to bottom of why the dehumidifier failed - if the installation description in OP is accurate it shoulnd't have run at all - same conductor to both sides of the utilization equipment input leaves no voltage across that equipment.

If it were hooked to two ungrounded conductors supplying the 120 volt rated unit with 208 - I'm surprised it lasted half an hour. Maybe internal overload cycled several times before it gave up?
 
kwired said:
... I'm surprised it lasted half an hour. ...
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A console dehumidifier, along with most other refrigeration machines, will have a hermetically-sealed motor with cold refrigerant gas passing directly over the motor windings. It's a very-effective cooling method. There was no smoke apparent because it was all contained inside the refrigerant plumbing.
 
drcampbell said:
A console dehumidifier, along with most other refrigeration machines, will have a hermetically-sealed motor with cold refrigerant gas passing directly over the motor windings. It's a very-effective cooling method. There was no smoke apparent because it was all contained inside the refrigerant plumbing.
Click to expand...
There is also a blower motor and with many newer models an electronic control board.
 
JamesBonded said:
. . . connected the first red wire to a single phase circuit and connected the other red wire . . . to another circuit on the same phase as the first red conductor. . . . The dehumidifier runs initially, but then burns out after about 30min of operation.
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For the dehumidifier to have run, let alone burn out, the wiring as described is simply wrong. Facts are missing. As described in the OP, the dehumidifier was supplied by two red wires with zero volts between them.

James, do you have the ability to verify the initial hookup? Pictures? We can't answer from what you've written.
 
al hildenbrand said:
For the dehumidifier to have run, let alone burn out, the wiring as described is simply wrong. Facts are missing. As described in the OP, the dehumidifier was supplied by two red wires with zero volts between them.

James, do you have the ability to verify the initial hookup? Pictures? We can't answer from what you've written.
Click to expand...

Key phrase from the OP:

... to another circuit on the same phase as the first red conductor.
Click to expand...

We do not know how qualified the OP (a construction manager rather than an electrician) is to determine that.
Possibly it is connected to another circuit on the same side of the panel as the first breaker. That could seem to be the same phase to someone who does not know how the panel bus crosses over internally.
 
Wow, I am truly surprised at the number of answers I got from you guys! Thank you all for taking the time to offer up a response.

I wanted to clarify the two red wire issue. I didn't actually see the wires myself, but rather my Assistant PM reported that to me. He's a sharp guy, but relatively unexperienced in electrical matters, and likely didn't get his explanation right. That being said, the only reasonable explanation is that one red wire was connected to one phase, and the other red wire was connected to another phase, which resulted in 208V.

Thanks again for everyone's help with this. I know exactly where I'm going the next time I have an electrical-related question.
 
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