Run SER cable to junction box, the installation correct?

EngineeredElectric said:
What are y'all building that requires 500 sets of 2/0 4C SER to be sent through a fire wall?
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Modular apartments; presumably 500 separate fire walls:

Size the junction box for SER Cable Splicing

This is a multifamily building project with modular apt units. Each apt unit is delivered to the site from the factory as a module. It has a 4#2/0 & 1#1G AL SER Cable whip. We need to make connections between the SER cable from the modular unit to the 4#2/0 & 1#1G AL MC Cable from the building...
forums.mikeholt.com
 
winnie said:
Modular apartments; presumably 500 separate fire walls:

Size the junction box for SER Cable Splicing

This is a multifamily building project with modular apt units. Each apt unit is delivered to the site from the factory as a module. It has a 4#2/0 & 1#1G AL SER Cable whip. We need to make connections between the SER cable from the modular unit to the 4#2/0 & 1#1G AL MC Cable from the building...
forums.mikeholt.com
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I still want to know the 'Type', A multifamily modular apartment project is not automatically Type III, at least I dont think it is, just because it is modular. Modular construction is a construction method, not a construction type. If the project uses a Type IA podium and say a roof above is carried by a noncombustible steel structural frame, the upper portion could be Type II rather than Type III.
 
tortuga said:
A piece of advise since your a professional engineer, and you asked, one thing to ask first is the 'Type' of construction and occupancy classification, as this limits the wiring methods you have available.
For example under the code rules for SE cable it points back to part II of the rules for NM cable which I believe is limited to Type III construction or higher.
The last time someone was asking me about a metal sleeve for SE cable thru a fire wall it turned out SER not an approved wiring method to begin with as they were in Type II-B Noncombustible (or limited-combustible) construction, and also another common gotcha for non-metallic wiring methods on commercial is in the chapter 5 articles like details in Articles 518 or 517.
Also I don't know about Philly but I have gleaned on here a few large cities like NYC and Chicago do not permit NM or SE cable in general not sure if thats the case still in 2026? but you might check what local rules Philly has?, as it says your in Philly.


Thats quite a few boxes.
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Thanks for the advice. Yes, we always consider the type of construction. Many residential mid-rise building has type I or II construction for the basement and 1st floor. And the type III constructions for the upper levels residential part. In this case, we only allow NM cable inside the apt unit. And for this projects, these modules located at the upper levels which are Type III constructions.
 
zemingduan said:
I guess it's 1hr or 2hr rated dry wall, definitely not brick or concrete wall. This is also what I want to figure out. Do you have to use the sleeve? What is the clean way to pass the SER cable through that wall to the box that is attached to the opposite of the wall?
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I realize that the SER cable pass through the wall and enters into the back of the box which is mounted on the opposite side of the wall. I think you are not able to install the SER connector in the hole/wall. It needs to be accessible.
 
zemingduan said:
I think you are not able to install the SER connector in the hole/wall. It needs to be accessible.
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One method to install it is by clamping it to the cable, caulking it in, then threading it onto the box. Once installed, it does not need to be accessible. There is also possibility of installing it inside of some boxes instead of outside... but it usually wouldn't be fun...

Do they make snap-in connectors for SER that size?
 
I do believe them make that clamp connector female to emt. Doubt its on the shelf at the box store in that size.
 
winnie said:
On what basis do you think that the SER connector will need to be accessible?
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I thought all fittings need to be accessible after installation. But code actually only requires fittings in lieu of a box or conduit body need to be accessible. So the locknut inside the junction box for the SER cable connector need to be accessible, but the connector body/clamp is not necessary to be accessible after the installation. Am I correct?
 
zemingduan said:
I thought all fittings need to be accessible after installation. But code actually only requires fittings in lieu of a box or conduit body need to be accessible. So the locknut inside the junction box for the SER cable connector need to be accessible, but the connector body/clamp is not necessary to be accessible after the installation. Am I correct?
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Correct.
Sberry said:
It was late and wrote last night but had an opinion and not a fact. This might be something to test fly by everyone along the way. I can see a one off,,, the risk is low but to stab 500 of these looks like a plumber did it and wait to see how it turns out is another matter.
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If you have a listed firestopping system or an engineering judgement to back it up, and submit it to the AHJ for approval with the planset, there will be no problems unless the AHJ is a complete clown show. If you don't submit it first... yeah, you might get to pay for your education, as they say...
 
Near every cable in finished resi has the clamp covered and even has the wire stapled. A reason for a pipe may be access to conductors. Its no good if it cant be serviced. If there was a change in resi design,,,, might require access over and under panel and thru the overhead or foundation etc Now its just practice.
Millions of older homes look like the wire was an after thought.
 
jap said:
My mind is still boggled by 3 phase apartment panels.

Jap>
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We design the electrical for the module only. There is another site engineer that deign the electrical system for the building and insist 3ph electrical for the apartment due to voltage drop is a big issue.

They have 480V incoming to the building and use (2) 750KVA 480V -208V transformer in the basement and distributed with 208V in the building. I suggest them to distribute with 480V in the building with multiple smaller transformers on each level if voltage drop is big concern. But they want to stick with their way. :D
 
jap said:
My mind is still boggled by 3 phase apartment panels.

Jap>
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Yeah since neither the optional calc under 220.82 nor the 83% rules under 310.12 would apply to a 3-phase dwelling unit I'd never consider going that route. You can still use 220.84 for the entire service, but between having to use the general calc to calculate the load for each unit and not having the 83% rule unless I am missing something seems like wasted $$.
 
I don't feel we have the whole story on this install.

To me, a splice would have to be made in the J-Box.

I just don't see U-Pulling a 2/0,2/0,2/0,2/0,#1 SER cable through a 10x10x6 SC J-Box.

Especially with the cable entering in the center in the back.

Oh well, I'm probably looking at it all wrong.

Jap>
 
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