[R-390] Re: Electrical panels and grounds...

[Gregory W. Moore]

This story reminds me of an incident which happened during the early 
'80's. I had a friend who used to bother me for all his 
electronic/electrical repair needs, with absolutely no thought of time 
or compensation. At any rate, he was calling me after an unsuccessful 
bout with the cable tv company about reception in his house. I don't 
know exactly why I said I would go over and "take a look" ( I believe 
the XYL kind of insisted that I go, as she was friends with HIS XYL, 
still is, as a matter of fact) but I did, and I probably saved his house 
by so doing.
        When I got there, I noticed that indeed, the cable was messed 
up, in fact, it was just about nonexistant. I decided to take a look in 
his basement where the cable entered the house, and found what the cable 
company euphamistically referred to as a "ground block" virtually 
MELTED, and the cable leading from this melted object, out of the house, 
with the outer cover actually MELTING in some spots, and the whole thing 
extremely hot. On doing some checking around the various "grounds" I 
found that they were, in most cases "hot" anywhere up to line volts. I 
started looking around, and found , (it was raining at the time) that 
this idijit was using a pump to drain his swimming pool, the pump had an 
exposed motor, and the whole mess was soaked, hot (both temperature and 
voltage). I figured I should check why the neutral and grounds should be 
so "hot", and found that, for some reason, the neutral had come loose 
inside of the service entrance panel, the panel was grounded to a water 
pipe (note, the pipe was PLASTIC, a fact which nobody was willing to 
take credit for, and the whole mess was, because the cable was grounded 
to the same clamp, along with the telephone (that still worked, 
amazingly) the entire system was grounded through the shield of RG-59 coax.
    Carefully pulling that stupid pump off line, I proceeded to pull the 
main fuses, and reconnected the neutral to the buss bar. I also went and 
purchased an 8' ground rod, proper ground wire, and some Greenfield to 
protect the wire, as I didn't trust this idjit not to destroy it with 
carelessness, went through the exertion of pounding that sucker into the 
dirt under the basement floor, and grounded everything properly. I also 
moved the bonding clamps off the plastic on to the copper, but stopped 
short of doing a whole bonding check, since at that time, everything was 
OK groundwise. I also highly recommended the services of a plumber SAP 
to get rid of that stupid plastic pipe (That was the ONLY piece of 
plastic in the whole system, and why someone would have installed it, 
let alone put bonding clamps on it is a total mystery to me) . Called 
the cable company, told them what had occurred, and that this idjit was 
going to need an entirely new coax, and the tap at the pole was probably 
trashed as well, got the usual "you're probably trying to steal cable 
service" response, which seems to be the standard cable company knee 
jerk answer to any intelligent discourse with cable tv service, not that 
I cared,  and the incident was over. NO  I didn't get reimbursed for 
either the rod, my time, nor my knowlege, but I probably saved his 
house-- My XYL was (and still is) happy that I got involved,  so 
everything was as it should be --hi hi--.  I have a hearty respect for 
grounds, I always had, but this was proof positive of a failure mode 
which I had not previously seen.

    I do enjoy the "glowing ground buss" and "...then he said a very bad 
word and backed out
slowly..." Sounds like an exciting day indeed, and much more impressive 
than the story above--hi--

73 de Greg Moore WA3IVX



Kenneth G. Gordon wrote:

>This thread reminds me of a short story Roberta Barmore told us 
>on the Glowbugs list a while back. She is Chief Engineer at a big 
>combined AM/FM/TV station in the midwest somewhere, and a 
>ham.
>
>She was walking by the main three phase panel which fed power to 
>the entire transmitter site and noticed that it seemed to be 
>somewhat warm. Then a few evenings later, she thought she saw a 
>slight reddish glow, so she called an electrician. 
>
>He showed up the next day, and after putting down some thick 
>rubber mats, and removing the panel, crawled back in under the 
>panel and looked up. 
>
>Her words were, "...then he said a very bad word and backed out 
>slowly..."
>
>Apparently the center one of the very large copper buss bars was 
>glowing red hot. When the panel was assembled at the factory, the 
>assembler had misaligned the center buss bar when drilling the 
>mounting holes in it and had offset it to one side or the other by 
>quite a distance. There was a very small gap between it and one 
>next to it. Further, the bolt holes were damaged in such a way that 
>the bolts couldn't properly clamp the buss bar to its mount, so the 
>current carrying capability of the buss bar was signifcantly 
>lessened. So much so that it heated up with the current load and 
>loosened the bolts, making it hotter yet, and so on.
>
>They had to cut the station power WAY back to keep the panel 
>from burning up while waiting for the replacement panel.
>
>Ken Gordon W7EKB
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