Old BX

[Chuck Ramstack]

I'm a Home Inspector not an Electrician. Living in the Milwaukee area I inspect a lot of what we call "Milwaukee Bungalows". Homes built after WWII. 2 storys mostly brick. For the most part they are all wired with BX. 90% of them have had the service panels upgraded from 60 amp fuse to 100 amp circuit breakers which is code here in order to sell your home. I recently inspected a home where the previous owner tore out the plaster walls & ceiling in the dining room exposing all the wiring. In testing the wiring I found it grounded properly etc. The owner asked if he should hire an electrician and have it rewired as long as it was all exposed?? I really didn't know how to answer him other then to tell him to have a licensed electrician come in and have him look at it. Since my own home was built in 1948 and is wired in BX I have to ask the question for future reference. Is 50 to 60 year old BX safe? If one of my customers indicates to me that he plans on doing some remodeling should I inform him to "budget" for rewiring his entire home? If they stay there any length of time now you have 80/90 year old wiring. Thanks for any advice I can give them.

 

[76nemo]

From the get go.

From the get go.

If it was done right in the first place, sure it can be safe. If you'd like to travel up North where I am, I can show you K&T that would make that BX look young. It's all in how it was wired from the get go. Have you looked any further into the installation? E.G., are all of the receps three wire, or grounded?

With all that said and done, it would be favorable to have someone licensed come in and look behind you.

 

[Chuck Ramstack]

Thanks for the reply. Some of the receps have been replaced others have not. Since the boxes are metal they are all grounded back to the panel anyway correct?? Same with the switches? I guess my main concern was attic runs etc. Doesn't copper get brittle after a period of time? Some of the BX I've come across is also covered with a stranded cloth material. Maybe I'm just being over cautious but when I inspect a home my first concern is for my customers safety and I don't want to lead them down the wrong path. Electrical is number one, furnaces are number two. Fireplaces number three and so on..............

 

[winnie]

Change your question.

Rather than asking 'Is the wire in the wall safe?', ask 'Is the wire in the wall sufficient?'

Given the extensive changes in the way electricity is used, it is very likely that there is a need for more general purpose circuits, better control of lighting, more kitchen circuits, bathroom GFCI, etc. Quite aside from the safety of the cable in the walls, there is probably a need to rewire simply from a usability standpoint.

If the cabling in the walls is sufficient to meet modern needs, then it is quite likely that the bulk of the wiring is safe. Unfortunately, the key problem areas will be the terminations near heat producing devices, such as lights. There you may find that the old insulation is brittle and falling off the conductors. This is safe when undisturbed, but ripping down the walls probably means changing fixtures. When the replacement fixtures go up, the insulation will crack, and then you will wish you could rip down the walls and put in new cables.

Given the above, if the walls are down anyway, I would probably recommend a rewire, even if the bulk if the cables in the wall are actually safe.

Please note: I work in electric motor research, not as an electrician. My experience with old BX is limited to 'DIY' work on my own home.

-Jon

 

[captaincrab55]

Chuck, Keep in mind that the BX was once connected to a fuse panel. Fuse panels were great if the proper fuses were installed. Who knows how many times the wrong fuses were installed. If the walls are open already, new wire would be the way to go.. If the walls are closed, get the pro's to check for past overheating signs and grounding..

 

[Chuck Ramstack]

<FONT face="Times New Roman" color=blue size=3>Thanks for the insight guys! Things I never considered. I remember now my old man jamming any size fuse he could find into the fuse box just to get the power back on. </FONT> And Winnie your right if your going to remodel chances are your going to want to add say, can lights, GFI's etc etc. Plus now that I think about it I'm sure Codes have changed since the 40's, electrical practices, and who knows if back then if you needed a licensed electrician to do the work? I do know abit about plumbing and carpentry and get into new construction as well. It scares me to see some of the workmanship in some of the homes........................
Thanks again

 

[don_resqcapt19]

One of the issues with old BX is the current carrying capacity of the equipment grounding path. It does not meet current standards and there have been reports of the armor glowing red without tripping the OCPD. I think that Joe T has some pictures of this happening.
Don

 

[Pierre C Belarge]

Actual BX, the amour is not listed as suitable for an equipment ground/effective ground fault current path.

The wiring may generally be in good shape, just remember it is old. If there were any substantial loads on the cable, it could have taken its toll over the years.
Meggering may be the way to go, or forego the cost of meggering and use it towards a rewire.

My sentiments - replace the wiring if at all possible.

 

[LarryFine]

My ever-so-humble opinion is that, as long as the original wiring was done properly, and the conductors haven't been overheated, there is absolutely no benefit from replacing existing wiring.

There are exceptions, but if the wiring is not being asked to supply loads beyond intent, it's as good as the day it was installed. If additional, EGC-needing loads are added, run a new circuit for them.

 

[Pierre C Belarge]

My ever-so-humble opinion is that, as long as the original wiring was done properly, and the conductors haven't been overheated, there is absolutely no benefit from replacing existing wiring.

There are exceptions, but if the wiring is not being asked to supply loads beyond intent, it's as good as the day it was installed. If additional, EGC-needing loads are added, run a new circuit for them.

Insulation ages. The OP says it was installed 50-60 years ago. I cannot see the conductors being as good as the day it was installed.

And when the walls are closed, who knows how long they will stay installed after that...

 

[76nemo]

I never gave an opinion on loads introduced to once loaded calc's. My opinion was for the ruling on older BX only. If the loads are fine, than so can be the original installation.
But with that in mind, how can the predicted loads decipher to the applications now considering they were planned 50+ years ago?

They can't. Bring in someone who can run #'s and calc's.

 

[augie47]

built in heater

built in heater

don's mention about the jacket becoming a "heater" caused one of the AHJ's in this area to prohibit BX long before changes were made in the manufacturing. he has since gone the way of much old BX, but he stated he had seen the jacket "glowing red" in more than one installation.

 

[Chuck Ramstack]

I REALLY appreciate all the comments! I've learned a ton. I guess I'm going to follow Pierre' lead for the following reason. Many of these homes, mine included, are in neighborhoods that are going through revitalization.
There are newer homes down the street from me that are selling for $450/$500/ K. Mine is a brick Cape Cod built in 1948 that needs ALOT of work.
My point I guess is that if I remodel it, like I'd like to, it may be around for another 60+ years. If what most of you are saying is true having 120 year old wiring in this place at some future date gives me the chills. I think my best bet is to rip the old wiring out and have a competent electrician replace it.
THANKS AGAIN!
Chuck

 

[76nemo]

I REALLY appreciate all the comments! I've learned a ton. I guess I'm going to follow Pierre' lead for the following reason. Many of these homes, mine included, are in neighborhoods that are going through revitalization.
There are newer homes down the street from me that are selling for $450/$500/ K. Mine is a brick Cape Cod built in 1948 that needs ALOT of work.
My point I guess is that if I remodel it, like I'd like to, it may be around for another 60+ years. If what most of you are saying is true having 120 year old wiring in this place at some future date gives me the chills. I think my best bet is to rip the old wiring out and have a competent electrician replace it.
THANKS AGAIN!
Chuck

It's nice to have members as appreciative as yourself aboard. Keep writing in:smile:

 

[480sparky]

It's nice to have members as appreciative as yourself aboard. Keep writing in:smile:

I wish all first-time posters would follow up on our responses. Seems all to many post their situation, we all bounce ideas around, then never hear back from the OP.

 

[76nemo]

I wish all first-time posters would follow up on our responses. Seems all to many post their situation, we all bounce ideas around, then never hear back from the OP.

Maybe we cause them to think too much???????