Monday, March 10, 2014

Pullung New Wire Through Existing Greenfield



The house I'm buying has mostly the old cloth covered wire. The inspector said that much of it is in greenfield and that it is possible to pull new wire through greenfield. I have never done this (I've only pulled new wire through conduit) - is it difficult? Any suggestions to make it easier? How do I know if I'm dealing with greenfield or standard b/x?
Thanks in advance!

Can you remove a switch or receptacle cover and determine what you have. Is the main panel exposed so you can see what you've got? TURN OFF THE POWER BEFORE YOU INSPECT STUFF. Let me know.

I haven't moved in yet - but accompanied the inspector. we saw the flexible armored cable in the attic and basement - I assumed it was b/x but he said it was greenfield (I don't know tell the difference - any hints?). Most of the The wires in the fuse box were older - some looked to have the cloth wrap over rubber insulation. Is that enough info? If not, let me know what else to look for. I've done extensive electrical work - but typically new wiring (either new b/x or fishing t/w through conduit). Green field is new to me - I never considered the possibility of pulling new wires through it.

If it is 14 ga or 12 ga wire and has cloth insulation on the wires and the flexible cable is 3/8 in diameter, then it is BX style older cable. It is not legal to use 3/8 flex except as a whip in short sections.
The NEC would not recognize pulling new wire through 3/8 flex.
Sorry
Wg

Thanks for the response - I'll have to look more closely at the diameter to determine if it's b/x or not.
As far as using b/x for anything longer than 3 feet - I'm aware that it's not code. But as a homeowner in Cook county (Chicago) IL - where we still can't use romex even though the rest of the world seems to use it without problems - we homeowners routinely use 25 to 50 foot runs of b/x because it doesn't raise any eyebrows when it seen in exposed applications in these old homes. Plus - if plastic sheathed romex is considered safe - how could armored cable be considered less safe?
We Chicago area homeowners view the ban on romex and the limitations on b/x as a power play by the unions to force the use of conduit - which is harder for a homeowner to install. Similar outdated code restrictions exist against cpvc (although I personally prefer copper) and PEX (which to be fair is still relatively new).
Thanks for the info!
Ed

I feel a need, no it isn't the bathroom type need, but clerifacation of knowledge for your confusion.
In todays market you will find no BX cable on the market.
In todays market you will find what looks like the old BX cable but in reality is Metal clad cable or type AC cable. Both have either a grounding conductor with thermoplastic insulated wires instead of wax paper style insulated wires. Also the old BX cable does not have a grounding wire or grounding strip in its construction. Metal Clad cable includes a grounding wire with the circuit wires and type AC cable has a grounding strip that with the flexible metal conduit both make up the grounding conductors in this type AC cable.
I suspect you should find that the short lengths of 3/8 limitations concerning any 3/8 equipment is because of the small diameter invites damage to any wire attempted to be pulled through longer lengths of that 3/8 flex.
Hope this clearifies the material for you.
Wg

Hey Edbreyer, Your original question is about putting new wires in greenfield. Dont confuse everything. Greenfield is flexible conduit thats it. It is possible to put new wires in. Depending on how long the piece is you can get lucky and push a wire right through. YOu can also try and 1/8 fish tape. If the Greenfield runs up to an attic or it is exposed somewhere you can have a helper straighten out or shake it to help your wire through. So if it is greenfield you can do it. And about the part of using BX in cook county. Go head use it, use it all you want. It creates nothing but a mess and is harder to add stuff at a later date. If they had used conduit in your house you wouldnt be here now would ya. Have a house done in flex and see how many times you trip over it and tangle up in it when your in the attic.

Thanks for the response - I'm hoping I'll be able to pull new wire through the greenfield (assuming that's what I have).
I agree about the conduit being the best - and wish they'd used it many years ago in this house. If I ever build a house (where romex is allowed) I will certainly price out conduit versus romex and hope I can afford the conduit.
However, - using armored cable is SO much easier in retrofit applications versus trying to install conduit in finshed walls. It's often the only reasonable/practical choice in these old houses.
I was happy to learn (via this posting thread) that b/x is not the same as today's modern cable - thus my confusion about about b/x length restrictions. Turns out that the NEC does in fact allow long runs of modern Armored Cable (but not the old b/x). It had always seemed strange/illogical to me that most of the country allowed romex - yet I kept hearing that b/x could only be used in short runs. Now it makes sense.
So, in retrofit applications in my house - where conduit is impractical - I will continue to use armored cable even if local codes happen to frown on it. I'm concerned about safety - not about local codes that have been drafted to protect special interests - Trust me, that happens a lot here in Chicago :^o
Don't get me wrong - I know union electricians are top notch - I just resent it when a rule's intent goes beyond safety - to generate more business for the expert conduit benders (it really is an art) and drywallers (to repair the opened walls). Thankfully, armored cable allows me to avoid those expenses.
Thanks again for the advice.

Originally posted by edbreyer
Thanks for the response - I'm hoping I'll be able to pull new wire through the greenfield (assuming that's what I have).
I agree about the conduit being the best - and wish they'd used it many years ago in this house. If I ever build a house (where romex is allowed) I will certainly price out conduit versus romex and hope I can afford the conduit.
However, - using armored cable is SO much easier in retrofit applications versus trying to install conduit in finshed walls. It's often the only reasonable/practical choice in these old houses.
I was happy to learn (via this posting thread) that b/x is not the same as today's modern cable - thus my confusion about about b/x length restrictions. Turns out that the NEC does in fact allow long runs of modern Armored Cable (but not the old b/x). It had always seemed strange/illogical to me that most of the country allowed romex - yet I kept hearing that b/x could only be used in short runs. Now it makes sense.
So, in retrofit applications in my house - where conduit is impractical - I will continue to use armored cable even if local codes happen to frown on it. I'm concerned about safety - not about local codes that have been drafted to protect special interests - Trust me, that happens a lot here in Chicago :^o
Don't get me wrong - I know union electricians are top notch - I just resent it when a rule's intent goes beyond safety - to generate more business for the expert conduit benders (it really is an art) and drywallers (to repair the opened walls). Thankfully, armored cable allows me to avoid those expenses.
Thanks again for the advice.
Ill be real suprised if u can pull that wire out thats gonna be one sucky job.If i had the choice of doing that or rewiring the house id rewire the house probably easier.Dont even attempt it.

I agree - I'm now formulating my contingency plan for running new wire to the second floor. I'll probably run about 6 circuits up to the attic and come down into the second floor walls from there. Looks like I'm in for loads of fun - but I've done similar jobs before.
Thanks!

It is specifically against the minimum safety standards in the NEC to use any flexible metallic conduit [aka greenfield, flex, etc.] that is smaller than 1/2 in lengths longer than 6'.
Wg






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