Aluminum Sheathed Cable

[Mongo1953]

Hi, All,

I am doing a renovation on two identical mid to late 60's built 11 suite apt bldgs. They took out the wall between the kitchen and living room in each unit, and I have to make the kitchen light switch leg they left dangling in mid air good, among other things. The apts have drywall/stick partitions, poured in place concrete cielings with emt between boxes, cinderblock exterior walls and suite separators.

My problem is the building has some of the branch ccts run in emt, (wherever they needed more than 2 conductors) the rest with aluminum sheathed cable. I have no experience with this stuff. It has a continuous smooth aluminum sheath, is stiff and doesn't pull out of the walls very easy. There are 2 #14 tinned copper conductors in it and no ground conductor. I presume the sheath provides grounding path.

It lands in a connector similar to a single screw bx connector but with a small diameter hole, I presume to prevent doubling up in the connector.

Should I be replacing this stuff? If it's ok to be left in place as legacy install, can I run from a box fed with this stuff with a new grounded romex? Nothing comes up sounding similar on Google or in the forum search. If anybody knows the trade name and current status I'd be grateful. I vaguely remember working with this stuff back in the early 70's.

I'm not shy about calling an inspector, but it's the weekend and I'm working on this tomorrow due to very tight scheduling.

Regards;

Mongo1953

 

[LarryFine]

I believe the sheath is lead, not aluminum. A quick test will tell you whether the sheath is bonded. As with K&T, it's okay if it hasn't been overloaded.

It also depends on whether your renovation is massive enough to require a 100% up-to-date compliance. Here, 50% of total floor area is the threshold.

I would definitely ask the inspector before doing any work involving it. I doubt this is his first exposure to it if he works the neighborhood regularly.

 

[Mongo1953]

Thanks, Larry. I know an inspector I can take up on his call me anytime offer tomorrow am. Any one with experience dealing with lead sheathed cable with no grounding conductor in renos, would appreciate hearing from you.

 

[Mongo1953]

Oh, and the scope of the reno is not that much. Electrical work at present is to relocate the kitchen switch from the removed partition, install a separate cct for new dishwasher, and separate cct for small apartment sized washer and dryer. These little suites ony have an 8 cct Federal panel that will be full when I am done.

 

[Smart $]

...

Should I be replacing this stuff?

I don't believe it to be required. But I recommend wearing gloves when you work with it.

If it's ok to be left in place as legacy install, can I run from a box fed with this stuff with a new grounded romex?

I don't believe you can add any new wiring to any existing circuits. Regardless of whether the sheath is grounded or not, the sheath is not a required type of grounding conductor per 250.118. For any new wiring, you have to run it all the way from the panel to be compliant, IMO.

You most definitely need to talk to an inspector (aka AHJ) on relocating the light switches. If you cannot do so simply by rerouting the existing switch-leg cable, he may require the entire circuit be wired anew with compliant grounding.

 

[Smart $]

I don't believe you can add any new wiring to any existing circuits. Regardless of whether the sheath is grounded or not, the sheath is not a required type of grounding conductor per 250.118. For any new wiring, you have to run it all the way from the panel to be compliant, IMO.

At the very least you will have to run a grounding conductor per 250.130(C).

You most definitely need to talk to an inspector (aka AHJ) on relocating the light switches. If you cannot do so simply by rerouting the existing switch-leg cable, he may require the entire circuit be wired anew with compliant grounding.

Again, at the very least you will have to run a grounding conductor per 250.130(C).

 

[Mongo1953]

Thanks, Smart. I agree with the grounding comments. I can physically remove and replace the lead sheathed switch leg with romex to the kitchen light outlet. The outlet box has a bonding screw. However, it is fed with the same stuff, there is no emt or bonding conductor to it and I don't think I can get that out. I am going to see if I can ground the new switch leg outlet box by running a grounding conductor to a nearby properly grounded box.

Job seemed straight forward till this stuff showed up. I will pick up some cotton gloves for handling the lead, too. Thanks for that.

 

[Volta]

I don't believe it to be required. But I recommend wearing gloves when you work with it.

Yes, it may be lead. Limit your contact with it, and mutiple disposable gloves may be the way to go. But it may be aluminum. Both have existed.

I don't believe you can add any new wiring to any existing circuits. Regardless of whether the sheath is grounded or not, the sheath is not a required type of grounding conductor per 250.118. For any new wiring, you have to run it all the way from the panel to be compliant, IMO.

These days. But ALS or Aluminum Sheathed Cable appeared in the NEC in 1962. The sheath was to constructed to be "an adequate path for equipment grounding purposes". Though you may have trouble finding connectors rated for such. I don't like a description of a set-screw type, but maybe a Speed-Loc or similar would be reasonable here. Or even a Neer C-500. Not rated for such, but seems to be similar to a C-510, which is rated for grounding.

The radii of the bends is larger than NM. In 1962, they couldn't be less than:
Ten times for cables not larger than 3/4" in diameter,
Twelve times for 3/4 to 1-1/2",
Fifteen times for larger.

I would figure out if it is lead or aluminum first though. No Articles for lead-sheathed in the 60's.

 

[Mongo1953]

Thanks, Volta. I am going to confirm this am whether or not it's lead. And I know aluminum sheathing was considered good for grounding. Haven't ran into aluminum sheathed since I was in the service. Never saw lead sheathed except on high voltage cables connected to potheads and the like.

My day is starting to look better. Heading out soon.

 

[infinity]

So what kind of cable is this? Smooth tube MC cable?

 

[Volta]

So what kind of cable is this? Smooth tube MC cable?

Pretty much the same, I think. If it is ALS, it is not considered MC, but may effectively be the same thing. It was described in NEC 1968 as:

. . . is a factory assembeld cable consisting of one or more insulated conductors enclosed in an impervious, continuous, closely fitting tube of aluminum.

The same year MC was described:

. . . a fabricated assembly of insulated conductors in a flexible metallic enclosure. See Section 334-4.

334-4 allowed 'metal-clad cable' to be either of an 'MC' or 'AC' series. The 2-conductor ALS or similar lead-sheathed I've seen (not much of either!) has been a flat oval similar to NM while any 2-conductor AC or MC tends to be round. Is the smooth MC of today corrugated or a continuous tube (like Mineral Insulated)?

 

[Smart $]

... Is the smooth MC of today corrugated or a continuous tube (like Mineral Insulated)?

It can be... but likely a special order. What is typically used is with a metal band formed to interlock then spirally lapped.

 

[Volta]

It can be... but likely a special order. What is typically used is with a metal band formed to interlock then spirally lapped.

While I was looking into the ALS this morning I stumbled across CS- Copper Sheathed Cable, Article 332. It was in the 1975 code, not 1971, nor the 1978. Seems like MI on a budget. :grin:

Type CS copper-sheathed cable is a factory assembled assembly of one or more conductors, each individually insulated and enclosed in a liquidtight and close-fitting continuous copper or bronze sheath.

 

[PetrosA]

I've never seen the AL clad, but they did use the Pb clad here as the predecessor to UF for underground and masonry wall applications.

 

[LarryFine]

I've never seen the AL clad, but they did use the Pb clad here as the predecessor to UF for underground and masonry wall applications.

Underground use is where I saw what I called lead-sheathed earlier. I remember the cable having some kind of white hairs as filler.

 

[Mongo1953]

Hi, all;

It's not lead. Smooth Aluminum sheathed. 2 #14 copper with some kind of fibrous/rubbery but tough insulation. Didn't see any hardening, deterioration in light outlets or wherever.

I looked long and hard today at the way these suites were wired and was able to avoid any changes downstream of any of this stuff and still got the job done with everything properly grounded. I did decide to rework some stuff I did yesterday, so this little project is not going to make me wealthy. But, the customer is happy, I'm pretty sure what I'm doing will pass inspection, and they have a bunch more work they want me to quote.

If I am able to learn more about this stuff, I'll put it up.

Time for a glass of wine. These 12 hr days are getting harder to string together.

 

[Volta]

Cool, glad it worked out!