80 year old conduit

[clare]

but you can ground all boxes the same way you do if wiring with "Romex" and there is no possibility of a hot raceway. I believe that is still code compliant.

[philoÂÂ]

Duh, I never thought of that. Will try later.

OTOH I now think it's probably not steel as I used to cut up "commo" wire when I was in the Army. That has steel and aluminum strands and is very hard to cut.

[philoÂÂ]

I am heading off to get some ground clamps now and will try to get all grounds down to less than an ohm.

If that does not fix it, I will have to replace the run.

The boxes have rusted screws and I'd have to chisel them off and re-tap the holes. All the BX feeds have poor grounds too. If I have to replace the BX and the junction boxes, it's going to be easier and better to replace all.

This house only has three original rigid conduit runs and the other two are perfectly OK, so I'm going to leave them alone.

When I bought the house in 1979 it had 30 amp, 115 service.

In 1932 that must have been pretty nice!

[dpb]

On 08/06/2014 8:25 PM, philo wrote: ...

He's saying if it were drawn it would tend to be work-hardened and hence stiff...there's some of that here, too, and while it is stiffer than modern Cu wire of same gauge, the stuff here that is like what you describe also is _definitely_NOT_ solid Cu--that can be seen w/ a freshly cut face. It is plated and like your supposition, I think it is a steel core altho I've not analyzed it carefully.

The reason I didn't respond here yesterday is that I thought I knew where there was a scrap laying around and went and looked thinking I could determine if it were, indeed, ferrous by the magnet test, but apparently I did clean up and tossed it. I did not find any old roll ends of it in a cursory look around the barn loft where all the leftovers and rework salvage is, unfortunately.

So, I still don't know more than the appearance and the certainty it isn't solid Cu--unless there was some other alloy that lost the characteristic Cu color.

Curiosity question -- what's the insulation material on what is there?

[HerHusband]

Just to clarify, code does not allow Romex to be run inside conduit, except for short runs for physical protection.

However, it would be a fairly trivial matter to pull out the old wiring and run new THHN wire in the old conduit. You could use the old wires to pull the new wire through.

Of course, if the conduit and boxes are exposed, I would probably take out the old work and run new boxes and cable. By the time you fiddle with stripped conduit and corroded terminals, you could have all new work installed.

Anthony Watson

[dpb]

...

On thinking, I'm not sure precisely what age/era this belongs too...it's not in the house which was built in 1915/-16 and originally wired K&T with a Delco 32V DC windcharger system as the power source...forward-looking for farmhouse in them days, was Grandpa... :)

Anyway, it probably is roughly depression-era as where I've found it is in the old farrowing house and some other add-ons since the earliest outbuildings/barn that were all in the period right around the house but before the coming of the REC in '48 at which time there was quite a lot of additional wiring added since then had the capacity for more than just a light here and there. There's also some (where I last worked on it, adding another yardlight control to the circuit in the second garage that hadn't ever had one since we've been using both since coming back to the farm) but that dates to, I think, the early 50s. I'm guessing it was wired with leftovers from previous work at that time being as how neither grandfather nor dad would have ever not used something on hand if possible rather than buy new if it suited the purpose...

With that, I'm wondering if indeed, it is an aberration owing to the Depression that was a cheaper alternative in times of trouble, but that's purely supposition. Some web searching has turned up no references to anything like it that I've found.

It's never been an issue in all the years it's been installed out here so while I've thought "that's odd!" when run into it, never did more to really look into it at the time.

[dpb]

On 08/07/2014 9:04 AM, HerHusband wrote: ...

...

That's not _exactly_ right. The tables in the back of the NEC have all the conduit fill info and include how to calculate the area of an elliptical cable and also how to treat a multi-conductor cable as a single conductor for fill calculations and as well as the temperature derating info for the conduit.

The "prohibition" is for NM in conduit without the additional derating for the conduit required, but that isn't blanket exclusion entirely.

That said, the difficulties in pulling NM instead of single THHN runs makes it such that one would choose the latter in almost all cases, anyway.

[philoÂÂ]

I don't have time to do any work now...but the coating is cloth covered rubber.

I just got back from Home Depot. I was going to buy some ground clamps...and I ran into the electrician who put in the 200 amp service and told him what I was up to.

He said it is OK to bond around a bad electrical ground...however the mechanical connection should still be good...which it is not...

So I am going to to the right thing and replace all...but not today.

BTW: The ground clamps were more expensive than I figured and all total would cost about the same as Romex and a few junction boxes.

[philoÂÂ]

Because I was in the battery business and studied the history , I have seen documentation on those 32 volt systems. There were even manuals showing you how to make your own lead battery plates!

Yep, I make use of leftover parts all the time!

BTW: Since my house was made in 1898 and they did not start to wire houses here until at least 1905 I was lucky that it was wired in 1932 and does not use knob and tube.

With knob and tube, even if the insulation breaks down, the ceramic insulators will keep things from shorting...

HOWEVER: Years ago the parents of one of my daughter's friend asked me to check out the wiring as their daughter was getting shocked when she took a shower. The knob and tube wiring was in the wall behind the bathtub and moisture had gotten in and created a conduction path.

I killed the power to that line and told the mother to call an electrician and have that circuit entirely replaced.

Later I found out she just turned the power back on and ignored my advice!

No way would I take a chance like that...they later sold the house.

[clare]

If it is pre-rural electrification all bets are off and it COULD be iron core wire. If it was wired for 48 volts DC there was no enforced code at the time. There has never been an "approved" branch circuit conductor made of iron in Canada or the USA. It is used extensively in power distribution, and in copper clad form, in RF distribution where skin effect makes copper clad wire just as good as solid copper - with higher tensile strength and lower cost. It has also been used for telephone distribution cable.

[dpb]

On 08/07/2014 11:39 AM, [e-mail] wrote: ...

The original locations were DC, yes, but I'm not sure of all of what might have been available options in the early 30s when the farrowing house was built/wired. It did predate REA reaching us by quite a long period, though, as that didn't happen until '48 (folks began collecting petition/formation signatures in early '45 before V-J day and the co-op was formed very shortly after the end of the war but it took almost 3 years to reach us with the lines towards the west end of their service area and Dad was on board from its originizational meeting for 50 yr).

Well, while that may well be true, that philo has what seems to be the same material as here shows it wasn't at least unheard of for there to be something other than Cu in the time frame that seems to coincide with that of this here.

I asked at the coffee shop this morning if any of the other old codgers had any recollection -- one fella' suggested the core might be nickel-silver (or "german silver")...would meet the indications of the observed visual characteristics. I'll have to do some more serious digging around and see if can't find a spare chunk to do actual 'spearmints with which...

[gfretwell]

The raceway itself is still supposed to be bonded. This is normally handled by the connectors into the bonded(grounded) boxes.

[gfretwell]

That is a common misconception but not true. The biggest problem with Romex in conduit is "fill:" You have to compute it as a conductor the size of the widest dimension. It is also pretty hard to pull. (no nylon jacket like THHN)

I think Philo was talking about abandoning the conduit altogether tho.

[gfretwell]

derating is by conductor count (and a few other factors). The fact that it is a cable in a raceway does not change that.

[philoÂÂ]

Took the junction box apart and disconnected the wires.

Cleaned them well and saw that they are pure copper...the "steel" color was due to tarnish and also the tinning from being soldered.

The threads on one pipe were stripped so I decided to just sand them to bare metal and slip a 3/4" EMT conduit connector onto it. The connector was slightly large for the pipe so I made a sleeve from a short section of 3/4" conduit.

Punched a larger hole in the box to match the fitting and put it all back together. Then put bonding grounds on the three BX sections and got my ohm meter out.

Now I have the resistance down to about 0.3 OHM and a good mechanical connection at the junction box.

Whew.

[gfretwell]

Good to go!

[dpb]

I was thinking I remembered the temperature-rating tables were based on conduit or no, as well, though??? I didn't recheck the recollection though, granted.

[dpb]

...

While the main house and barn, etc., were wired and ran on the Delco, grandfather was thinking ahead and the wiring was done with eventual power in mind. All that needed changeout when connected to REA was the DC switches (of which I still have a half-bushel basket full of the push-button Victorian-era mother-of-pearl buttons for those who are in dire need of same. :) )

Was interesting when still doing coal analyzer support for Sask Power there're still enough farmsteads there that there was a co-op store in Weyburn with DC appliances on their showroom floor (as recently as about '95, anyway).

[dpb]

...

And, just to clarify we're not totally still in the dark ages, the folks essentially gutted the house in the late '70s before moving from our "little house" next door. All new plumbing/wiring/insulation added/etc./etc./etc., ... then.

Most all the main outbuildings were drastically upgraded in the 60s after Dad took over the operation from grandfather and we added quite a lot more ground and larger cattle operations to get with the changing times and particularly after the 50s drought broke there were some good years that allowed for some investment. So, other than just these few locations like the aforementioned garages, the old shop, the farrowing house (now totally unused except for storage), etc., that have nothing more than lighting circuits for a few overhead bulbs and (maybe) an outlet or two, it's all pretty much up to what was Code at that time...I've never worried about much of the newer Code changes as never could see any real need as was discussed in an earlier thread.

[dpb]

...

Huh. So now I've the only extant installation with this bizzaro wire???