Identifying Older Wiring Size & Type

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Krim

Senior Member
Hello,
I am trying to find out how to accurately identify both the size and type of an existing in ground service that runs from an outdoor mounted main panel to another building about 800 feet away. There is no identifying marks on the cable at either end and going by the physical dimensions it is closest to 300 mil stranded aluminum with a THHN insulation of which I know it is not !
The insulation is somewhat like a rubberized 14-3 cord ? I don't know what the standard cable types were when this was installed in the 70's so I could use a little help from the more experienced electricians out there,please.
I'm trying to avoid having to run new underground wiring.
Thanks,
Carl
 
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Physis 3

Guest
I'm having a problem believing that you're an electrician.

You should be able to identify wire gauge.

You should know the cable type or say something about what type it most looks like . Your description sounds odd. Which also causes me to ask other questions. Something like THHN in something you're describing like an extension cord? :confused:

You can't look up a wire gauge diameter, but you know enough to measure it?

I'm not saying you're not an electrician, just asking the question.
 

mdshunk

Senior Member
Location
Right here.
There are a few companies out there that make plastic gauges you can slide over the exposed conductor at a lug to gauge it. The insulation type you describe sounds like probably type RW, but it's hard to say. Safe to say it's a 60 degree conductor anyhow. There was some neoprene stuff during that era too, and I'm not sure what the insulation type was. Maybe they called that type R also.
 

infinity

Moderator
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Location
New Jersey
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Journeyman Electrician
Physis 3 said:
I'm having a problem believing that you're an electrician.

You should be able to identify wire gauge.


A little harsh don't you think? He's only asking a simple question.:rolleyes:


Back to the OP, could be TW or THW insulation if it's from the 70's. Or possibly RHW if it's older. RHW would have a braided silk like outer covering over rubber insulation. TW and THW would be similar to THHN if you stripped off the nylon jacket on THHN and exposed the insulation beneath it.
 
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Physis 3

Guest
I guess you're right, I don't want to be mean to anybody.
 

Krim

Senior Member
To clarify what I'd written, yes,according to the wire tables the physical dimension of the afforementioned aluminum multi stranded conductor is a size 300 . However the physical overall dimension falls in the range nearest that of a THHN insulated conductor. There is not a nylon jacket nor any noticeable means of identification on the outside. As for comparing it to a
14-3 rubberized extension cord I meant , but didn't write, more specifically that the insulation is comparable to that of a 14/3 ,black, round, SJ cord. OK ?
By the way "THANKS" to Trevor aka infinity for your response and professional reply !
 

infinity

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Staff member
Location
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Occupation
Journeyman Electrician
Carl Ewing said:
By the way "THANKS" to Trevor aka infinity for your response and professional reply !

You're welcome, and Physis did apologize. :cool:

One more question, are you positive that it's aluminum? The old rubber insulated cables had tinned copper strands to keep it from reacting with the rubber insulation and can appear to be aluminum.
 

Krim

Senior Member
Trevor,
Yes, Physis did apologize and I've accepted ! Now to move on .
I am absolutely positive that the conductors are aluminum .
The best result is that now the 200 amp panel is not large enough for the equipment they need in and around the building so they've decided to outsource having another service installed. I'll just have to do the easy part of running everything from the panelboard now to the devices.
Thanks to all for your input !
Carl ... How do I end this post ?
 

roger

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Location
Fl
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Retired Electrician
Carl Ewing said:
How do I end this post ?

You don't, it may take on a life of it's own or just fade away when the posts stop.

Roger
 

Krim

Senior Member
roger said:
You don't, it may take on a life of it's own or just fade away when the posts stop.

Roger
Roger,
So the posts on the forum are kinda like the energizer bunny ?
They keep going and going ..... !
Ha,Ha. Thanks , I needed that reply to end my day :) !
Carl
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Carl Ewing said:
Roger,
So the posts on the forum are kinda like the energizer bunny ?
They keep going and going ..... !
Ha,Ha. Thanks , I needed that reply to end my day :) !
Carl

Actually the bunny wouldn't stand a chance against some of the past threads, click HERE for 781 reasons as an example.

Roger
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Carl Ewing said:
Roger,
WOW ! That post really went too far !
Carl

Now that's an understatement if I've ever heard one. :D

Roger
 
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