I got two electricians to come out and look at my 1939 house. I wanted to see if the wiring needed upgrading.

One person opened up a receptacle and said I had cloth insulated wires and that I need to rewire the house...including bringing everything up to code. This includes adding outlets to walls that don't have it. It includes adding hardwired smoke and CO2 detectors. It also includes re-wiring all the light fixtures too. Cost ~14k

Another contractor went up to the attic with me and saw old metal conduits and said that it was actually in good shape. He said that as long as the wires are inside the conduit it would be fine. He also saw that in the house there were some receptacles that are not grounded, have ground and neutral reversed, no neutral or ground... I asked him about cloth wire and he didn't seem to think that was an issue. As long as it is in conduit it was okay. Cost: ~$800 to make sure receptacles are grounded and properly wired.

Who should I listen too?


picture of conduit

This is the type of conduit in the attic. It may be BX (armored cable) as mentioned by by @ThreePhaseEel.

Here's a picture in our kitchen. Old junction box and metal conduit. One goes to the floor the other goes to a hardwired garbage disposal. junction box and conduit

updated 9/16

The house has 3 bedrooms, one bathroom, a small dining room, a living room and a kitchen (total ~ 1400 sq/ft). Some outlets are actually grounded (at least that's what my tester tells me).

iopened J box

Update 9/21/16

The outside of the wire actually feels a little tacky...almost rubber-like.

  • 1
    Can you modify your question to explain what you're trying to achieve? Why did you call the electricians out in the first place? Commented Sep 16, 2016 at 2:43
  • Can you provide some photos of this situation? Commented Sep 16, 2016 at 3:45
  • 1
    That looks like mc but hard to tell on my phone. I would get the outlets fixed at a minimum. If you have the available $ to replace the cloth it wouldn't hurt but if no modifications are being done and you have a breaker panel not fuses the total rewire could wait or be done a room or 2 at a time if you are remodeling.
    – Ed Beal
    Commented Sep 16, 2016 at 6:20
  • 2
    To me the $800 sounds a bit low, maybe will need more $ once work starts. But not knowing how many rooms, how many outlets are in that cost. If all wiring is in conduit for entire house then $14K seems a bit high (again how much work planned). If no aluminum wire was found any where in the house then it is just how the insulation is holding up in the cloth wire on how soon to replace the wire. I have pulled cloth insulation that was solid as can be but have occasionally found runs that crumbled, usually where the copper was darkened and the outlet was over loaded with multi-plug taps. Commented Sep 16, 2016 at 18:44
  • 2
    It's a myth that multi-plug taps cause overloads. If you run out of checks, does that mean your checking account is empty? No. It's how much you're drawing! You can overload a duplex outlet with two 1500W heaters plugged in neat and tidy. You can also run 50 cellphone chargers off an octopus of multi-plug taps and be nowhere near overload if their power factor is decent. Commented Sep 22, 2016 at 5:07

3 Answers 3


If you're going to have old wiring, it's pretty nice to have it in metallic BX. I would wire separate grounds (as NEC 2014 now allows) and make sure every box is grounded, and make sure your BX grommets are tight, conducting and not corroded so the BX is relatively well connected to ground at each end where accessible. At that point you're almost as good as EMT conduit, and that's pretty good for a domicile.

Add GFCI or combo breakers.

OK yeah, so the wiring is old. So what? What's the failure mode here? If you get a wire break, it'll arc inside all-metal containment (which will trip an AFCI if you use it) otherwise it'll arc until it snuffs (dead circuit) or it'll arc until it arcs to the shield, then it'll trip the GFCI. If insulation fails and a hot or neutral contacts shield, it'll trip the GFCI. You're golden.

  • This is really helpful...and puts my mind at ease. So: Are my options as follows: (1) AFCI breakers + GFCI outlets (2) AFCI/GFCI breakers (3) normal breakers + GFCI outlets + AFCI outlets. I'm leaning towards Option 1. I'll get AFCI protection and I can actually see which outlets are GFCI protected.
    – milesmeow
    Commented Sep 24, 2016 at 6:34

The old wiring in your house appears to be old-style AC (BX) with cloth insulated wires in a paper overall wrap under the spiral armor (no bonding tape). Its fault current capability in the event of a ground fault is limited -- the armor in this early BX, while grounded, is not up to current standards for an EGC (equipment grounding conductor). I would check the newer wiring to make sure that the EGCs are continuous to the main panel, and fix all the miswired outlets for that matter (i.e. reversed wiring on outlets).

You could replace the ungrounded outlets on the BX circuits with what are known as self-grounding outlets if you wanted some sort of ground connection on them instead of none whatsoever, but I'm not sure that's essential with modern levels of GFCI and AFCI protection.

  • It's funny that you mention fixing miswired outlets...there were definitely a bunch. And when we fixed them...after AFCI breakers were installed, other miswiring caused the AFCI breakers to trip.
    – milesmeow
    Commented Jan 14, 2017 at 3:29

If it were me, I'd leave it be; as long as everything was done with a reasonable amount of skill originally, it will be fine; if it's been modified a lot through the years, and there's visible issues (connections not in boxes, too many junctions, open wiring), that's another story.

If you want to spend money for peace of mind, spend it on arc fault sensing breakers, fire detection, things like that, and like others said, upgrade as you need if you're making other changes.

  • What is fire detection? Do you mean like a fire/smoke sensor that can notify you remotely?
    – milesmeow
    Commented Sep 18, 2016 at 0:32
  • if you're worried about the safety of the wiring, good smoke detectors are a must; and yes, those that can notify you are a great investment.
    – SqlACID
    Commented Sep 18, 2016 at 0:35
  • I researched AFCI breakers and those are awesome. All panels should have AFCI or AFCI/GFCI breakers!
    – milesmeow
    Commented Sep 25, 2016 at 6:25

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