Strange voltage in 1960's vintage manufactured home.

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frizbeedog

Senior Member
Location
Oregon
Cable Comany claimed that the home had improper grounding....and had measured from their cable (the conductor, not the shield) to the house ground and had measured 50 volts. Come to find out that this measurement was conducted at a surge protector plug strip and not at the outlet which was inaccessible (bookshelves).

They also said they were getting shocked when trying to connect their equipment to the side of the home (metal skin), and an associated ground which was attached to the trailer frame.

I attempted to measure the same way they did with no results, but had readings from 2 to 7 volts when measured to the shield.


Found the proper 4 wire feed installed via overhead connection to a post mount service adjacent to the home.

The only abnormal voltage readings I had were these:

All circuits on:

Line 1: 114 V
Line 2: 132 V

Turn on and off various circuits an found two circuits that, when both were "off", brought the voltages back to normal:

Line 1: 123 V
Line 2: 123 V

One circuit was connected to a multi-wire branch and the other was connected to a 2-wire branch. Both of these had to be off for the voltage to return to normal. At the request of the customer, these findings were not investigated further.

I installed a ground jumper (a length of 12 guage) and connected it back to the service and used it to measure for potential differences on various points of the trailer skin and frame. None found.

When all was said and done, I had recommended that the cable company ground their system directly to the service ground at the pole next to the trailer as the phone company had done.

Brain trust, what say you.

:smile:
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Sounds like a possible loose connection on the neutral at the POCO transformer, with a combination of a poor grounding electrode field at the service. Especially when your voltage stabilized with no load.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Could be a fault also from a neighbors trailer that was not properly grounded also, after rereading your post though, you are saying it's only on two peticular circuits?
 

frizbeedog

Senior Member
Location
Oregon
Strahan said:
I agree. Why did the customers not want you to investigate any further? I would think they would want the problem resolved.

Cash Flow.

:smile:

The Cable company said there was a problem with the grounding. Whether my voltage readings had anything to do with that or not, I don't know. As far as the customer knew, there was no problem until a Cable tech. said there was.
 

Strahan

Senior Member
Location
Watsontown, PA
frizbeedog said:
Cash Flow.

:smile:

The Cable company said there was a problem with the grounding. Whether my voltage readings had anything to do with that or not, I don't know. As far as the customer knew, there was no problem until a Cable tech. said there was.

I had a similar problem with the house I just sold. L1-N 120V. L1-G 50V N-G approx 50V. I found contractor or previous owner never connected ground wires in a j-box hidden above ceiling. Yea this was a real chore:cool: Too bad owners didn't let you proceed but during these times the cash flow problem can be understood.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
i've never heard a manufactured home called "vintage". normally at that age, dilapidated is the correct term. :)
 
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