Resi panel has all branch circuit entering through 1 MA

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tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Ok, I was up for this challenge of, is it legal to run one mombo Pvc connector to run a whole panels branch circuit system through, which I've seen and to me is lazy as , well you know ...

If I was an Inspector I'd say .. check 334.30 ... right were is says within every support within 12" of enclosure such as outlet boxes cabinet or ( fittings ) the key word is then fittings or should I say approved fittings, a pvc fitting does not maintain the clamp or crimp that a NMB connector possesses, So the argument would then be, what is an approved soft sheathed connector, does it need to be lightly compressed to prevent slippage. Anyone care to contribute to the question of using a pvc fitting or even just a large chase nipple. Besides I'm sure there's a violation just by having 3" of cables crammed together like that.

check 334.30 (A) other than they refer to horizontal I'm sure the NEC board would consider this as an applicable situation, as noted : and the non metallic sheathed cable is securely fastened in place by an approved means of each .. .. cabinet .. ( or other non metallic cable termination )

PVC connectors are not non metallic cable termination fittings.
Excellent point, 300.15Fittings and connectors shall be used only with the specific wiring methods for which they are designed and listed.”
The standard used to investigate products in this category is ANSI/UL 514B

From the UL white book section:
NONMETALLIC-SHEATHED-CABLE CONNECTORS (PXJV):
MARKINGS
Connectors which are also suitable for use with service-entrance cable, flexible nonmetallic tubing or flexible cord are so indicated on the device or carton.
Except for duplex connectors or when otherwise marked on the carton to indicate connecting of more than one cable or cord, the connectors covered under this category have been investigated for connecting one cable or cord
only.”


RELATED PRODUCTS
Connectors covered under Armored Cable Connectors (AWSX), Conduit Fittings (DWTT) and Power and Control Tray Cable Connectors (QPOZ) are also suitable for use with nonmetallic-sheathed cable when specifically indicated on the device or carton.
Connectors suitable for flexible cord only are covered under Outlet Bushings and Fittings (QCRV).”

No mention of a PVC fitting.
 

sparky1118

Senior Member
Location
Massachusetts
Occupation
Master Electrician
First off, there should never be mc and bx going thru a large hole. They need to be connected to the panel.

There is never a good way to do this compliantly. IMO, I would leave it except for the bx and mc and fill the connector with some sealant.

Why would you want to go thru the bottom of the panel. An outdoor panel cannot have nm cable run to it if the nm is exposed.

I have argued this with Iwire many years ago. He insisted you could drill individual holes and bring them into the back of a panel. I would love to see someone install 30 circuits, with 30, 40 and 60 amp conductors on some, and get it into the back of a panel.

Imo, if you don't allow the installation thru the back then the outdoor panel is worthless. You could always install a JB on the back side of the panel and run individual wires thru a 2" conduit. That would work if you came out the back into a crawl area.... That just creates a tremendous amount of extra work

Speaking of Iwire is he okay? Haven’t seen him on in awhile


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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Iwire is enjoying his time away from the forum for now. That is all we know

So a TA is wide open and if something should go awry in a panel then sparks could jump out of the panel thru the TA. So maybe they should allow it if the connector was filled with fire stop after all the conductors were installed.

BTW, that bridgeport connector allowing 6 nm cables thru a 3/4" KO is $40.00. No thanks

The nec is written to protect us from the basic issues. You can think of a thousand things that the code requires even though there may not have been an issue. They do not wait for an accident to occur if something is obvious or counter to what we have learned.

I tried writing something to change this. All but one agreed with me and he actual wrote a long statement supporting my thoughts.
 

McLintock

Senior Member
Location
USA
Occupation
Electrician
So a TA is wide open and if something should go awry in a panel then sparks could jump out of the panel thru the TA. So maybe they should allow it if the connector was filled with fire stop after all the conductors were installed.

.

That is the most reasonable answer to this question I have heard, and it makes sense. You want the panel inclosed IN CASE something goes wrong and off track.

So what is the best product to use in connecting NM to a panel?


“ shoot low boys their riding shetland ponies”
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
These are the 2 most commonly used to penetrate metallic enclosures that I've come across, the metallic connectors range from 1/2 up to 1-1/2 I believe. Typically Inspectors out here will allow 2 possibly 3 cables per connector.
Romex Conn.jpg
 
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Aledrell

Senior Member
Ok So the picture of above with all the numb through the top of a 2” ma in the center ko wouldn’t fly here in AZ, for a recessed panel. Although unlike many of you, our meters/all-in-one load centers are exterior mounted and located (we don’t have many basements here.). And a 2”-2.5” MA with lick ring has been trade standard for years when it comes to getting nmb circuitry inside the panel. They are individually staples within 12” of the MA.


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infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Ok So the picture of above with all the numb through the top of a 2” ma in the center ko wouldn’t fly here in AZ, for a recessed panel. Although unlike many of you, our meters/all-in-one load centers are exterior mounted and located (we don’t have many basements here.). And a 2”-2.5” MA with lick ring has been trade standard for years when it comes to getting nmb circuitry inside the panel. They are individually staples within 12” of the MA.
I'm curious, although you don't have basements why do you still put the panel on the exterior of the house? I would think that an interior panel in a garage would be better and if there is no garage then it can go in the wall inside of the house.
 

Aledrell

Senior Member
So the utility companies here wanted the meter on the exterior so their readers could read it monthly. Then they had issues with meter clips burning up bc people would change the load center without the meter. So the utility mandated that all new panels be a meter and circuit breaker together in one can so residents would basically upgrade the meter sockets for them whenever the box was upgraded. This reduces services calls for the utility and gets the customer to upgrade what is essentially their equipment.


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infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
So the utility companies here wanted the meter on the exterior so their readers could read it monthly. Then they had issues with meter clips burning up bc people would change the load center without the meter. So the utility mandated that all new panels be a meter and circuit breaker together in one can so residents would basically upgrade the meter sockets for them whenever the box was upgraded. This reduces services calls for the utility and gets the customer to upgrade what is essentially their equipment.

So the utility company mandates that the panel needs to be on the outside of the house? Our meters are outside too but the panels almost never are.
 

Aledrell

Senior Member
Yes they do mandate it in a way for residential. I think you can have an inside load center if your willing to install a large 200A fused lever disconnect switch after the meter. BC we have another code and I’m not sure if it’s NEC or local that says the FD needs to be able to turn off all the power to a residents with 6 switches (breakers) or less. $500 fuses disconnect or $175 panel with meter...kind of easy to see why no one goes against the grain.


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hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I'm curious, although you don't have basements why do you still put the panel on the exterior of the house? I would think that an interior panel in a garage would be better and if there is no garage then it can go in the wall inside of the house.

THANK YOU!!

Yes they do mandate it in a way for residential. I think you can have an inside load center if your willing to install a large 200A fused lever disconnect switch after the meter. BC we have another code and I’m not sure if it’s NEC or local that says the FD needs to be able to turn off all the power to a residents with 6 switches (breakers) or less. $500 fuses disconnect or $175 panel with meter...kind of easy to see why no one goes against the grain.

Well, the 2020 requires a disconnect outside and I'm sure there will be meter/disconnect combos commonly used.

It's always been my opinion that panels belong inside the building mainly to protect them from the elements but also for accessibility. Now that AFCI GFCI breakers are required with their electronics, you don't want them exposed to condensation and moisture. You also don't want people crawling around outside in the rain, snow or behind shrubs or trees especially at night. Locations for inside panels need to be accommodated in house design, no excuses.

Installing a panel outside is plain stupid.

-Hal
 

McLintock

Senior Member
Location
USA
Occupation
Electrician
These are the 2 most commonly used to penetrate metallic enclosures that I've come across, the metallic connectors range from 1/2 up to 1-1/2 I believe. Typically Inspectors out here will allow 2 possibly 3 cables per connector.
View attachment 2552463

I have come not to like the metallic connectors, I have seen a couple of them have burr’s on them and short the wire out, and newbies get them to tight and short it out.


“ shoot low boys their riding shetland ponies”
 
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