Does an older house need to be rewired?

Question

I am rehabbing one apartment in a 1937 triplex in Los Angeles I just bought. Looks like the electricial wiring is original two cloth-insulated wires, although the kitchen and bathroom have three-prong GFI outlets. The main panel supplies 100amps for the whole building. The inspection didn't point out anything about the electricials, so I am trying to determine how much work is required vs what is nice to have. To rewire the whole building to modern codes and upgrade the power supply to 200amps would cost 15k. But what do I need to do? Can I get away with the existing wiring? I know new construction must be to code, but what about older buildings?

Kevin M. · Answer

Can you get away with it?  Depends on the jurisdiction, inspector, and level of rehab you're doing.  If you can get away with it, should you?  Depends on your moral compass.  That old wiring is pretty sketchy, the insulation usually falls off with just the slightest touch.  Any critters or other movement could expose the wiring within the walls/ceilings with palpable risk of fire.  Making things worse, most of those types of homes don't have adequate fire/smoke alarms. Given the chance, I replace it...it might mean that I don't get a record profit on the project (or any at all), but I sleep well knowing I've done the best I can.

That being said, 15k for a re-wire and panel upgrade it pretty steep for one apartment.  You might be able to find a more attractive offer.

Updated electrical is a prerequisite for me in choosing s rehab.  The work updating electrical yields almost no return but can be quite costly and time consuming.  I've yet to meet a prospective buyer who enters the house and says "look honey, this one has a new electrical panel, and receptacles!"  Nevertheless, once you've gone down that road, it's a very strong "should" do.

Scott Mosley · Answer

Disclaimer: I am not an electrician and do not play one on TV. I am not remotely in the same league as some the professionals that have responded.

The experts that have already replied have given some very sound, logical advice. If I happened to be in your situation, which I have been, I would rewire. We did with one home located in Long Beach(Belmont Shore) this past April. It ironically was built in 1937 as well.

Something to keep in mind going forward; it is our understanding that many homes built prior to 1939 used sandstone foundations and obviously older "cloth type / knob and tube" style wiring.

1940+ homes builders started utilizing cinder block foundations and bx wiring, which is as mentioned a ground wiring system.

All the best

Mark Elliott · Answer

hello, aleko. i am a home inspector from the western new york area. the old cloth, 2 wire wiring is kind of dangerous, in my opinion. as stated earlier, the cloth gets brittle and can crumble with the slightest of touch. with rehabbing the place, you are going to disturb it, for sure. then, you have exposed wiring. fire hazzard. not to mention, a lot of this old wiring is made of aluminum, not copper, therefore, the heat it will carry without fail is far lesser that the copper type wiring. if you have an overload somehow, and the breaker doesn't trip, you are going to have a fire. the gfi's have to be grounded, thats the whole idea of a gfi. the g stands for GROUND. with the two wire system you have, where is the ground???? you don't have one, hence, your gfi's could not be hooked up correctly.

i agree, the $15k sounds a bit steep for the total rewiring job. i would shop around for the best deal you can find, but i would definitely do it. yes, of course it would " pass inspection" as is, if a home inspection was about pass or fail, but it's not about pass or fail. its about the condition of your home at the present time. and at this present time, the wiring is working as designed. is it safe??? no, but it's working. a good inspector would have told you that it is in working order, but has many potential dangers.

Paul Sorgi · Answer

Hmm two cloth wires?  Do you mean it is knob and tube wire?

If so you want to replace it.  Technically when updating a panel you will only need to supply a new feed to the point that the knob and tube enter the walls or ceiling.  This could buy you sometime but it is best to run the feed the entire distance to the new receptacles.  Today electrical standards are far superior to 1937.  In 1937 house or apartments had very few circuits and the  code today  calls for 20 amp circuits to kitchens, a receptacle every 4' of counter space, GFCI near sinks, bathrooms and basements etc.

They bright side is a house built in 1937 might be very easy to fish the new lines.  I have always found away to get  a new wires installed in an old house.  There are usually nice large gaps along chimneys, vent pipes, outside walls, etc.  and then I just reuse many of the existing receptacle locations with new old work boxes and receptacles.

Bart Libsock · Answer

rewiring and old house is a pain i'm assuming its plaster and lathe. probably most of the 15k was for labor just to get to the wires, if a guy could trace  where the wires are routed maybe you could get a couple high school or college kids to sawzall out just enough channels so the sparky could refeed wires then cover the whole thing with rock, sometimes it works sometimes it doesnt. a 100 amp service is not alot for three units.

Aleko Petkov · Answer

That's a good point, Jeffrey! I hadn't thought of that. The property passed inspection and is already insured, but it's good to know exactly what the gaps are.

Jeffrey H. · Answer

Also check your insurance and general liability policy for the property.  Will it cover a fire due to old wiring or is that an exclusion?

Does an older house need to be rewired?

Most Popular Reply