Thread: Splicing in sub panel

Is it ok to splice within a panel as long as there is enough space?

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Yes and no.

Yes, but only if the conductors terminate within that panel.

No, in the photo, as the conductors do not terminate in that panel, one set of conductors comes in, the other set goes back out - and that is not allowed (the panel enclosure is not a junction box for conductors passing through it - because conductors should not be "passing through" it).

I concur and believe that's so worded in the 2005 NEC; 312.8.

And I'm going to disagree.

312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be
used as junction boxes, auxiliary gutters, or raceways for
conductors feeding through or tapping off to other switches
or overcurrent devices, unless adequate space for this purpose
is provided. The conductors shall not fill the wiring
space at any cross section to more than 40 percent of the
cross-sectional area of the space, and the conductors,
splices, and taps shall not fill the wiring space at any cross
section to more than 75 percent of the cross-sectional area
of that space.
(My bold)

As that reads "adequate space" and not "special, isolated or dedicated space", my interpretation of that paragraph is that it would be OK as long as the wiring space, described in the second sentence, is not overfilled. I don't know what else "unless adequate space" would refer to.

I did a search on the matter over at Mike Holt's forum. The general consensus is that it is allowed and that the confusion is caused when people stop reading 312.8 before they get to the "unless" bit.

...that is not allowed (the panel enclosure is not a junction box for conductors passing through it - because conductors should not be "passing through" it).

So...is there a more specific code prohibiting this, because I can't find it.

Putting codes aside for a moment, and looking at it from a practical safety POV..as long as the conductors pasing through have an OCPD upstream, why would this be any more of a hazard than splices in a junction box elsewhere in the home?

Originally Posted by Richard Moore

And I'm going to disagree.

As that reads "adequate space"

No, it reads "unless adequate space for this purpose is provided." and the space "is not provided for this purpose". (Your bold highlighted the reason it is not allowed.)

I did my checking with UL Standard 67 (the standard to which they are listed and label to) and UL. According to UL, there is no space in any panelboard which "is provided for this purpose". They (the engineers I talked with at UL) said that if a manufacturer would like to provide space for that purpose, a test could be designed, and parameters made for those tests, resulting in stated limitations "for this purpose".

For instance, what if you wanted to run a single 20 amp circuit through the vertical section of a panelboard ... not much problem with that, is there? Other than it not being listed for that purpose.

However, take the instance that you wanted to run 2 sets of 200 amp feeders through that vertical section of a panelboard ... whoa, that's a whole different ballgame, isn't it?

Now, with no testing, no limitations, and no rating ... "for that purpose" ... *NO* conductors passing through are allowed. One cannot arbitrarily say 'Okay, that 20 amp circuit is okay, but the 200 amp circuit is not okay.'

The limitations for the use of that space: "The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space." are for when (*IF*) a manufacturer decides to have their panelboards tested, listed, and labeled "for this purpose".

Until then, and with respect to those on Mike Holt's forum, it is not allowed, not by the listing and labeling and not by the UL Standard 67 to which they are tested to.

Putting codes aside for a moment, and looking at it from a practical safety POV..as long as the conductors pasing through have an OCPD upstream, why would this be any more of a hazard than splices in a junction box elsewhere in the home?

Because, if the conductors passing through it are hot, and come into contact with conductor not passing through it (i.e., originating in the panel) are fed from an overcurrent device which is either off or tripped, those conductors *could be engergized by the conductors passing through the panel*.

Thus negating the tripped or off overcurrent device on those conductors. Can you say YIKES! ZAP!

Where is the prohibition against wires 'passing through?

Since the code requires a 'foreign power' warning label if wires pass through if the circuit does not originate in that panel, this seems to suggest wires 'passing through' are allowed.

More to the point, when lighting controls are involved, and operate several circuits, it's pretty hard to not have the wires 'pass through.'

There is such a prohibition that specifically applies to motor starters; I don't see any broader proscription.

Originally Posted by John Steinke

Where is the prohibition against wires 'passing through?

John,

Here we go again, starting back at square one ...

312.8 Enclosures for Switches or Overcurrent Devices. Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided.

There is the prohibition against it.

"shall not be used as" "junction boxes" "auxiliary gutters" "raceways" "for conductors feeding through".

Could the 2 conductors to that double tapped breaker be spliced to correct it??

Richard,

No, the two cables in question simply enter the panel, are spliced together, then leave the panel.

They are not intended to be connected to power within the panel.

Quote:

Putting codes aside for a moment, and looking at it from a practical safety POV..as long as the conductors pasing through have an OCPD upstream, why would this be any more of a hazard than splices in a junction box elsewhere in the home?

Because, if the conductors passing through it are hot, and come into contact with conductor not passing through it (i.e., originating in the panel) are fed from an overcurrent device which is either off or tripped, those conductors *could be engergized by the conductors passing through the panel*.

Thus negating the tripped or off overcurrent device on those conductors. Can you say YIKES! ZAP!

No. I'm sorry, I don't buy that. A panel may have numerous other hot wires, including the panel's own feeders and all the other circuits that "could" energize the conductors of a turned off OCPD. As long as the cables just passing through are properly insulated, like the rest of the wires in the panel, I still don't see that as a particular problem.

I can't argue with the UL stuff you posted. I don't have ready access to all UL findings or your interactions with them. Like most here, I'm simple folk just trying to do my job by interpreting the NEC.

So, yes, I did consider the "for that purpose" bit but I keep coming back to "wiring space" as the "purpose". If it was only allowed in specially designed enclosures, how hard would it have been to state that. I realize that the folks over at Mike Holt's forum aren't the last word on this, but I do find it odd that I can't find your interpretaion anywhere over there. If EVERY electrician is going to say it's OK what's the point in reporting it as in need of repair UNLESS it appeared to be dangerous...and it just doesn't to me.

However, take the instance that you wanted to run 2 sets of 200 amp feeders through that vertical section of a panelboard ... whoa, that's a whole different ballgame, isn't it?

LOL...that's a bit extreme, but, if they are feeders (and not unprotected SECs) and the odd panel in this very wierd set-up clearly had enough space for those insulated conducters to pass through, then yeah, I think I might be OK with it. But I'd sure want to see the whole bizarro set-up first!

Originally Posted by Richard Moore

No. I'm sorry, I don't buy that. A panel may have numerous other hot wires, including the panel's own feeders and all the other circuits that "could" energize the conductors of a turned off OCPD.

The difference is that you could turn *ALL* the OCPDs off in that panel, and that conductor running through *would still be hot* and *could still energize all the other conductors.

So, yes, I did consider the "for that purpose" bit but I keep coming back to "wiring space" as the "purpose".

That wiring space is provided for the wiring terminating in that panel.

If it was only allowed in specially designed enclosures, how hard would it have been to state that.

They did state it. How hard is it to read it?

312.8 Enclosures for Switches or Overcurrent Devices. Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices,

That what it states, first and foremost: "shall not be used as".

Then it gives an exception: "unless adequate space for this purpose is provided".

"for this purpose"

"is provided"

Cannot get much clearer than that.

I can't find your interpretaion anywhere

Not my interpretation. That is what the UL engineers said.

Thank you for your help everybody... great information.

"They did state it. How hard is it to read it? " Watch the tone Jerry! We're just having a, hopefully, civilized disagreement here!

"Cannot get much clearer than that." Well, I guess it obviously could be clearer!

Jerry, I find it interesting that UL lists NO panels for this purpose. None? Nada?

"The difference is that you could turn *ALL* the OCPDs off in that panel, and that conductor running through *would still be hot* and *could still energize all the other conductors."

The feeders or SEC's to that panel are still hot and I don't believe there is any code requiring no contact between the insulated feeder cables and any other conductor in the panel. So, I still don't see a big difference.

I went back over to Mike Holt again. This time I searched using "312.8". It comes up with 118 threads. They're not all relevant, but many are. Once again, the constant interpretation over there of "the purpose" is simply adequate wiring space. I have to assume that at least some of the moderators there are knowledgable electricians.

If we go back to the original photo, I don't see the pass through conductors as being a hazard, I (personally) can't find a code violation, and I wouldn't call it.

I know I'm not going to change your mind on this and, likewise, you are not going to change mine, so we will just have to disgaree.

Have a good one.

Richard,

The difference between us is:

You go to the middle man.

I go to the source.

The middle man is well respected and makes great sense, I know this because I was privileged to help Mike on his 2005 Changes to the NEC video.

The source, on the other hand, does not have to make interpretations, they go by what is written in the standard, they wrote if to fit what the manufacturers wanted to test. NO .. *NO* ... manufacturer wanted to test for allowing 'through current' on conductors running through the panels, just too many variables to be allowed for, thus the manufacturer (the one wanting to test for that) would be responsible for all costs in developing the standard test.

The end result 'would have been' a maximum current rating (temperature rise) with a maximum conductor size (wire fill space) and 'where' the conductors could be run, i.e., horizontally through bottom to bottom, horizontally and vertically bottom to top on same side, horizontally and vertically bottom to top on other side, vertically through top to bottom, you name the possibilities for placement, each would cause different temperature characteristics on different parts of the panelboard. Plus, they would 'most likely' have required a grounded metal divider separating those conductors from the rest of the panelboard.

Hopefully, you can begin to see how complex it could ultimately get.

It may have been possible that, had I not called UL and talked with several of their engineers about this already, that Mike would have been able to convince me it was okay, but, having already talked to the horse's mouth and been given all the why-for's, how-come's, and what-about's related to this, there is no way even Mike will be able to change my mind. Unless he has the power to convince UL that they are wrong, then they can convince me that they were wrong.

Jerry, I'd love to see the "UL man" put that opinion in writing.

As I read the NEC, you are specifically allowed to splice, or join, or pass through a panel, unless there's no room. "Room" being determined by the usual code box-fill rules.

I don't see the prohibition you infer. There's plenty of room.

Originally Posted by John Steinke

Jerry, I'd love to see the "UL man" put that opinion in writing.

He did.

As I read the NEC, you are specifically allowed to splice, or join, or pass through a panel, unless there's no room. "Room" being determined by the usual code box-fill rules.

I don't see the prohibition you infer. There's plenty of room.

I know you don't see the prohibition to which I refer (not infer - "refer"), so ... I will post it AGAIN - just for you John. By the way, it has been posted above already. And to your attention too. http://www.inspectionnews.net/home_i...html#post46994

Having a bad day reading, are you John?

312.8 Enclosures for Switches or Overcurrent Devices. Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices,

That what it states, first and foremost: "shall not be used as". The states what it "shall not be used as" - namely: "junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices".

That should be an easy read, John. What part do you not understand?

Then it goes on to give an exception - to wit: "unless adequate space for this purpose is provided".

"for this purpose"

"is provided"

Cannot get much clearer than that.

What part of that do you not understand?

You are only pulling out the words "unless adequate space ... is provided", you are ignoring the specificity of that exception. Namely that the space is provided "FOR THIS PURPOSE", and it is not provided "FOR THAT PURPOSE".

Sorry, I missed the post ...

I understand 'for this purpose' to refer to splicing as the purpose - it would be kind of silly to say a 'switch box is made for the purpose of switches.' Kind of redundant.

So, in general, splicing within an enclosure is allowed.

The exception, as specifically stated elsewhere in the NEC, is for motor starter enclosures.

Originally Posted by John Steinke

So, in general, splicing within an enclosure is allowed.

"In general" ...

As long as the conductor terminate within the enclosure and do not use the enclosure as a raceway, yes.

Otherwise, no.

Here's my tuppance based solely on the photo viewed on an iPhone.to avoid any problems later wouldn't it be an idea to pull the spliced wires out and splice them in a separate junction box?whilst your at it identify the two current carrying conductors with the correct colour phase tape .also it looks suspiciously like one of the spliced wires is a 3 wire Hhn and the other is a 2 wire hn without actually seeing the panel in question it also looks like there are differing wire sizes. Where is the spliced feeder wire coming from?another panel? I think there is more to this than meets the eye .as far as splicing in the panel, I've seen installations in high rises in NYC where two or three risers have been run in one pipe hitting two or three panels, with the respective current carrying feeders pulled at each panel and the neutral spliced and continued to other panels. An arrangement that I always considered dodgy.disconnect that neutral on a single phase feeder and you could potentially put 208 volts across 110 volt equipment a goodnight Vienna scenario . Your thoughts on this situation would be interesting

For those of you that think splicing conductors that pass through a panel and do not terminate in the panel is acceptable I suggest the following. Try doing it on a permitted job and bringing it to the inspectors attention and see how fast he fails your inspection!

When you turn the power of to a panelboard, all the wiring within the panelboard should be deenergized.

I'm not worried about wiring fed from another panel accidentally energizing wiring in the panel in question! I'm more worried about the electrician that comes to work on or replace that panel who diligently turns off the main breaker feeding that panel and goes to work repairing or replacing that panel getting injured or killed because live wiring still exists in that panel!

I don't need UL to tell me that's not right!

Acceptable exceptions are wiring fed from the panel going to a switch or a timeclock or lighting contactor and then back through the panel to the load. This is acceptable because the wiring still terminates in the panel it is passing through and if the panel is deenergized so is the wiring passing through the panel. This may stretch the "for this purpose" clause but it is acceptable in every jurisdiction I work in!

While we are on this subject I came accross this today and I have never seen this done and I am not sure how to respond. This appears to be a panel of sorts and it is full of splices. It the okay? I am thinking it isn't.

That looks like the original panel was there and someone didn't want a new panel there so they extended everything to the new panel location. The feeders have been extended to the new location and the wires from breakers in new panel have been brought back and spliced onto the old existing branch wiring.a simple panel swap at that location was not wanted, probably because during remodeling that wall would be behind something, like a kitchen cabinet.

Either that or someone did a seriously dodgy job and just used that box as a splice box for everything

It wouldn't surprise me if that box was buried

This isn't in NYC by any chance was it

Looks like one of those. What's the violation here quizes in one of the trade magazines

Personally now; as an AHJ I would have to agree with J.P. on this one.
Unless the panelboard manf. specifically lists their equipment for splices energized from other sources, a clear and present danger exists to any person who may de-energize the panel for service.

One issue still remains that I trust will create more disscussion...
Some generator transfer switch/panel boards utilize the main panel (if you will), to splice into the circuit conductors.
The main panel is required to include a placard stating "Two sources of power" or something to this effect.

Generac has used this method for many years.
What say Y'all?

Originally Posted by Craig Barr

While we are on this subject I came accross this today and I have never seen this done and I am not sure how to respond. This appears to be a panel of sorts and it is full of splices. It the okay? I am thinking it isn't.

If the box were sized correctly for the number of conductors it contains it would be fine. The problem appears to be the multiple cables into a flush mounted box. There is an exception that will allow cables into a sleeve entering the top of the panel. It is limited to surface mounted enclosures.

Originally Posted by Jim Port

If the box were sized correctly for the number of conductors it contains it would be fine. The problem appears to be the multiple cables into a flush mounted box. There is an exception that will allow cables into a sleeve entering the top of the panel. It is limited to surface mounted enclosures.

Also, the minimum sleeve is 18", and the cables are required to be supported and secured within 12" of the end of that sleeve, and the sleeve (raceway) is required to be sealed or plugged, among other requirements/limitations.

With the panel not being surface mounted I just left out all the other needed conditions.

Originally Posted by Jim Port

With the panel not being surface mounted I just left out all the other needed conditions.

Jim,

I understood that, but wanted to make sure the others knew that it was not just as simple as having the panel surface mounted ... just in case any of the others did not understand what you were doing.

Thats fine. The additional considerations you added just make the install even wronger.