Grounding in a old home

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buddog57

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My mother purchased a home built in 1942 which has no grounding at the service or the two sub panels.The upper floor has the old cloth covered two conductor branch circuits and the lower level has a very old romex type of wire with a small ground wire.I figure that the lower level was either remodeled or was originally wired at a later date than the upper level.All of the ground conductors are landed on the neutral buss with the neutral wires and someone had ran a #6 solid copper ground wire from the electric water heater and dryer to the neutral buss at the service and bonded the water heater and dryer grounds to it.
The feeders to the sub panels run through interior walls and a poured concrete wall so I can not feasibly run a new ground with them.I can bond the service to the city water line but I am concerned that if I do I will be creating net currents/electromagnetic fields in all of the circuits that have the neutrals and grounds bonded at the sub panel,plus the old wire is very brittle, if moved too much it cracks the old insulation.
My electrical experience is in the commercial/industrial field so I an not sure what to do about this, to make it as safe as possible, without ripping out the lath and plaster walls and rewiring the whole house.
I will be very thankful for any insight or information you could provide reguarding similar situations.
thanks,
Bob.
 
Re: Grounding in a old home

I think you already know the answer.It not easy but a rewire is likely needed.The old wire insulation is likely very brittle and the small grounds are known to melt.Perhaps just start with building a new service and slowly start rewiring.It can be done with little damage.Labor will be the costly part.On rewires i figure me and one good helper one hour each per outlet.Is there crawl space under it and an attic ?
 
Re: Grounding in a old home

There is a attic but no crawl space, the first floor is poured concrete walls built on a concrete slab.
Thanks for tour input,
Bob.
 
Re: Grounding in a old home

Hi Bob,
Is this a drop service with conduit through the first floor stemwall to interior subpanels? If this is a circa 1942 then there may be K & T in the attic for that era. That could help for fishing down and lighting upgrades but not a lot otherwise. Is the main 'block & fused' and with what service size? If the subs are in interior walls downstairs there may be an answer to least rewiring to above main floor. Please elaborate and I might be able to give better remod ideas.

rbj, Seattle
 
Re: Grounding in a old home

an acquaintance of mine bought a 1900s vintage home a few years back.

he ended up ripping out most of the old plaster walls to install modern plumbing and electrical circuits. I think it made him nearly cry.
 
Re: Grounding in a old home

he ended up ripping out most of the old plaster walls to install modern plumbing and electrical circuits. I think it made him nearly cry.
Click to expand...
Well I can't speek of plumbing But with the right tools and a little know how electric can be ran with little to no finish damage.

I have done three historic homes for the National Lake Shore park that one of the requirements was not to damage any finish surface and pull in all new 12 awg NM to every circuit. Yes it is very time consuming and testy at times but I get Er dun. :D
Now I get stuck with all the circuit additions!!! :roll:
 
Re: Grounding in a old home

I have never had to work on a very old home that did not have a grounding system and the owners wanted to put in a grounded system.
Instead of ripping out all of the plaster walls, I have wondered, "has anyone thought about installing wiremold raceways in their home".
It is just a thought, and I have used wiremold in commercial and in industry and sometimes I have seen it used in a residence.
 
Re: Grounding in a old home

Originally posted by hurk27:
he ended up ripping out most of the old plaster walls to install modern plumbing and electrical circuits. I think it made him nearly cry.
Click to expand...
Well I can't speek of plumbing But with the right tools and a little know how electric can be ran with little to no finish damage.
Click to expand...
He did manage to save some of the plaster walls by working from the back side. But when you have limited resources and the electrican wants something like $5000 per room to install the new electrical stuff if you want to save the plaster, sometimes you have to go with something affordable.
 
Re: Grounding in a old home

Hay buddog 57 I would start with the service an make the necessary upgrades, driven ground rod an bonding the water pipe. If your mother can afford it new service equipment would be the way to go and then just move on from there. If you tackle the house a room at a time its not so bad. I just hope you have somewhere accessible so you can put some junction boxes in an splice into the circuits later if needed. I am going through this same process right now, but the home owner is working with me and gutting some of the plaster mostly in the kitchen. It would be helpful if you can get someone to help you fish the walls when the time comes because sometimes you just need a 3rd hand.
 
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