Thread: 2X tap at FPE panel

Anyone happen to know if these terminals on a 1950s FPE panel are allowed to be 2X tapped with dissimilar material/sized conductors (feeders to an equally nasty FPE load-side panel)? I realize it's HIGHLY unlikely, but I've been fooled before...

(And ... yes, replacement of the whole mess will be recommended....)

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Michael,

As far as I know, none of FPEs terminals allowed double-tapping.

That's an ugly mess. It looks like three red wires are double-tapped in there to provide a 240 volt feed to the conduit on the lower right. Probably added by an unlicensed handyman. That means there is a red neutral somewhere that may not be marked as such. There is plenty of reason for replacement there.

Originally Posted by Michael Thomas

2X tapped with dissimilar material/sized conductors

In and of itself is a no-no.The rest is gravy. Unless otherwise indicated, the default is one per. Without an indication, no double tap, period; but ...disimilar material or dismilar size, disimilar type - not allowed.

The arcing and overheating is likely to be less at the double tap than at the bus, so it is not lkely to make a bit of difference. It does give you a good reason to call in an electrician and blame any future problems on them

Michael,
It appears there is many problems with this panel.
1. It appears to be an ungrounded FPE panel which should be recommended to be replaced.
2. The larger red wires at the main lugs appear to be feeding something which may not be protected by a breaker.
3. I also noticed other double taps at the lower breakers.

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Didnt we beat the double tapping issue to death about a month ago?

FPE= bad
double tap= bad
ungrounded= bad

Originally Posted by Mitchell Toelle

ungrounded= bad

Mitchell, Can you explain the ungrounded part. Thanks

Originally Posted by neal lewis

Mitchell, Can you explain the ungrounded part. Thanks

There is no visible grounding conductor coming into the panel. However, the panel is in Illinois, and grounded, most likely, by the conduit.

Originally Posted by Tom Mcdonald

Didnt we beat the double tapping issue to death about a month ago?

Tom, this board exists to beat issues to death repeatedly. We like dead horses!

Originally Posted by neal lewis

Mitchell, Can you explain the ungrounded part. Thanks

Not Mitchell here, but as pertaining to the discussion I took it (ungrounded - bad) to mean as pertaining to the conductor(s) being "hots" being 2x tapped.

Originally Posted by John Kogel

There is no visible grounding conductor coming into the panel. However, the panel is in Illinois, and grounded, most likely, by the conduit.

Bonded, John K. Lets not muddy the waters, and not all of Illinois has such tight restrictions and limitations on wiring methods otherwise permitted by Chapter 3, its mostly the NE portion of the state, but I digress.

Terminology differences between the US (NEC) and Canada (Canadian Electrical Code) I believe may be confusing you J.K.

As in, 2x taps of Ungrounded conductors (hots) versus 2x taps of grounded conductors ("neutrals"), versus 2x taps of grounding conductors ("bonding").

Distinctions with differences.

No, John was talking about whether the panel was GROUNDED, not whether it was BONDED.

Just so you know, HG:
GROUNDED. Connected to earth or to some conducting body
that serves in place of the earth.
BONDING. The permanent joining of metallic parts to form
an electrically conductive path that will ensure electrical continuity
and the capacity to conduct safely any current likely to be
imposed.

Originally Posted by Benjamin Thompson

No, John was talking about whether the panel was GROUNDED, not whether it was BONDED.

Just so you know, HG:
GROUNDED. Connected to earth or to some conducting body
that serves in place of the earth.
BONDING. The permanent joining of metallic parts to form
an electrically conductive path that will ensure electrical continuity
and the capacity to conduct safely any current likely to be
imposed.

I get "it" (and the nuances of the different uses of terminology in the two countries' model codes). YOU don't, as evidenced by your post.

Originally Posted by John Kogel

That's an ugly mess. It looks like three red wires are double-tapped in there to provide a 240 volt feed to the conduit on the lower right. Probably added by an unlicensed handyman. That means there is a red neutral somewhere that may not be marked as such. There is plenty of reason for replacement there.

Those are feeders to a FPE load-side panel, and neutral IS "marked"... but with BLACK tape.

Also, found this third panel behind an access cut into the drywall in the finished portion of the basement (power was off, so no way to know if it was still energized).

Originally Posted by Michael Thomas

Anyone happen to know if these terminals on a 1950s FPE panel are allowed to be 2X tapped with dissimilar material/sized conductors (feeders to an equally nasty FPE load-side panel)?

Not unless so identified.

I see nothing in your photos saying that two conductors is okay, that copper and aluminum together is okay, and the copper may well be too small for that terminal.

Did you by chance take a photo of the label on the panel? That would be the second place (actually, the first place) to look for that information?

If the label is gone or not legible, then there is nothing which identifies that terminal for that use.

However, I think I see copper in the "aluminum" where the tinned coating was accidentally scratched off, meaning that is tinned copper, which would not be dissimilar metals ... but would still be a problem with two neutrals in one terminal and the red one being too small (likely too small) for the terminal.

Originally Posted by Jerry Peck

However, I think I see copper in the "aluminum" where the tinned coating was accidentally scratched off, meaning that is tinned copper, which would not be dissimilar metals ... but would still be a problem with two neutrals in one terminal and the red one being too small (likely too small) for the terminal.

Good eye. At the time it looked to me like all the copper I could see were strands of the conductor entering at the bottom, but upon closer inspection of the hi-res photo one "copper" area (circled) could be it bit of scraped tinning... or a reflection of the camera's flash from the adjacent copper on an aluminum strand of the conductor entering from the top.

Guess we won't know unless the electrician complains about "the idiot inspector who can't tell tinned copper from aluminum".

However... did they even make tinned stranded conductors, let along ones large enough for use as SECs? All I've seen were solid, and don't remember any larger than 12AWG.

Originally Posted by Michael Thomas

However... did they even make tinned stranded conductors, let along ones large enough for use as SECs? All I've seen were solid, and don't remember any larger than 12AWG.

You mean you haven't seen tinned copper stranded cable such as used for marine grade battery cable even today? I'm not advocating the use of it or TEW (thermoplastic equipment wire) up to 4/0 at least IIRC for that matter, as SEC or tap, just referencing its existance, amongst others. From the apparent vintage of some of that equipment I wouldn't assume thermoplastics.

I don't think that's a revealed copper core from a tinned copper strand (but I don't have the photo enchancement skills you two do). I think perhaps you're seeing a strand of the adjacent cable behind a shorter nipped strand.

However tinned stranded copper is considered disimilar materials to (uncoated) copper stranded cable when it comes to sharing a terminal (Resistance/heating).

Originally Posted by H.G. Watson, Sr.

However tinned stranded copper is considered disimilar materials to bare copper stranded cable when it comes to sharing a terminal (Resistance/heating).

Thanks. Makes sense, but had not occurred to me.

MT,
I had made an edit for clarification (changed bare to uncoated, as "bare" usually refers to uninsulated), but I know you knew what I meant, regarding untinned vs. tinned copper strands.

Originally Posted by Michael Thomas

However... did they even make tinned stranded conductors, let along ones large enough for use as SECs? All I've seen were solid, and don't remember any larger than 12AWG.

Yes.

Most of the tinned copper I've seen has been stranded.

The copper was tinned to stop chemical reaction with the rubber insulation, thus all rubber insulated conductors, regardless how large, would have been tinned copper.

Originally Posted by H.G. Watson, Sr.

However tinned stranded copper is considered disimilar materials to (uncoated) copper stranded cable when it comes to sharing a terminal (Resistance/heating).

This is a bit interesting as fixture wire is often tinned and is intended to be connected to bare copper wire with wire nuts. Are we now to assume that (from at least your perspective) this type of splice is prohibited? If not, what is your point in bringing up the issue? Are you saying that, for example, a tinned wire and a bare copper wire couldn't be installed in the same terminal of a ground buss? Or are we just pouring gas on something hoping a fire will start?

Let me get this straight ... copper and tinned copper are now considered dissimilar metals?

That would make copper and copper-clad aluminum *not* dissimilar metals (the copper on the copper-clad aluminum making the contact *not* dissimilar in the same way that tinned copper is now dissimilar from copper).

Then why is it not that way in the NEC?
- 110.14 Electrical Connections.
- - Because of different characteristics of dissimilar metals, devices such as pressure terminal or pressure splicing connectors and soldering lugs shall be identified for the material of the conductor and shall be properly installed and used. Conductors of dissimilar metals shall not be intermixed in a terminal or splicing connector where physical contact occurs between dissimilar conductors (such as copper and aluminum, copper and copper-clad aluminum, or aluminum and copper-clad aluminum), unless the device is identified for the purpose and conditions of use. Materials such as solder, fluxes, inhibitors, and compounds, where employed, shall be suitable for the use and shall be of a type that will not adversely affect the conductors, installation, or equipment.

I guess that makes all those decades of actually soldering the copper together as well as making a mechanical connection created dissimilar metals junctions?

I guess that also means that tinned copper *is not* allowed to be connected to any device as no device I recall having seen was rated for copper/aluminum/tinned copper.

More information - please.

Tinned copper has a slightly greater resistance.It is NOT the same as untinned copper, especially in a stranded cable. In lower voltage applications not so much difference, but disimilar, just the same. At medium and high voltage it is significant enough to make a difference. Service equipment and panels similarly rated are at medium voltage exposure safety levels.It is the surface carrying of each strand, where the resistance is greater.When sharing a terminal you may also not share stranded with solid, so your "copper" argument is out gas.

Due to the nature of the FPE and the condition of the panel, not only would I highly recommend a replacement of the panel(s), I would also recommend a complete review of the entire electrical system by a qualified contractor. FPE breakers allow for additional amps to the wiring and with the improper modification, no one could guess what else they have done. Looks like a fire hazard to me.

Originally Posted by H.G. Watson, Sr.

When sharing a terminal you may also not share stranded with solid, so your "copper" argument is out gas.

While you're checking out things, why not look up the wire type combinations permitted to be terminated on a Cutler Hammer type CH circuit breaker, 10 thru 30 AMP.
Residential Products
Tab 3, Page 31 . (right side - under catalogs) Check note #2 at the bottom of the page.

Originally Posted by Bill Kriegh

While you're checking out things, why not look up the wire type combinations permitted to be terminated on a Cutler Hammer type CH circuit breaker, 10 thru 30 AMP.
Residential Products
Tab 3, Page 31 . (right side - under catalogs) Check note #2 at the bottom of the page.

The note in question: