Wiring methods for Mixed Commercial/Residential Space

Status
Not open for further replies.
T

tduval

Member
Location
Massachusetts
I am going to be doing some work for a commercial space renovation, making provisions for changing an old barber shop to a new hair stylist salon. The building has 2 commercial spaces on the ground floor (a salon and a bar) with 2 apartments on the upper floors. I was planning on using MC and pipe being a commercial space, but there is a lot of existing (some quite old, some looking fairly recent) romex feeding all spaces. What would you say is the proper wiring method for work in this space, the bar, and the apartments? The owner is suggesting future work in all of the spaces, possible service change as well. Thanks in advance!
 
Romex is acceptable in Mass. It's important to keep in mind that MA has amended the NM cable rules for a long time, and continues to do so. It's still allowable above a drop ceiling, and I assume you will have some of those.
 
peter d said:
Romex is acceptable in Mass. It's important to keep in mind that MA has amended the NM cable rules for a long time, and continues to do so. It's still allowable above a drop ceiling, and I assume you will have some of those.
Click to expand...

Although It is acceptable in Ma. it has to closely follow the framing members or running boards.
 
Have a look at ARTICLE 518 Assembly Occupancies for the bar, if you are not required to submit plans and go thru plan review I would call your inspector and find out what is typical for the area. Personally I find EMT preferable for anything and everything commercial. Especially over 30 Amps. MC would make sense for 15-20a circuits. I would avoid NM on such a project.
 
tortuga said:
Personally I find EMT preferable for anything and everything commercial. Especially over 30 Amps. MC would make sense for 15-20a circuits. I would avoid NM on such a project.
Click to expand...

You would not be competive here, cable is the norm here.

Up until the 2002 NEC we used NM a lot in commecial occupancies and while still allowed in MA MC is more common.

We commonly use MC for circuits from 2 to 200 amps and sometimes more.
 
iwire said:
You would not be competive here, cable is the norm here.

Up until the 2002 NEC we used NM a lot in commecial occupancies and while still allowed in MA MC is more common.

We commonly use MC for circuits from 2 to 200 amps and sometimes more.
Click to expand...


The master has spoken.
 
As mentioned if the bar is large enough to be a place of assembly - you can't use NM cable in there.

Otherwise under the right conditions you possibly can use NM cable in part or all of it.


See 334.10 and informative annex E on construction types and determine what NEC has to say. Some places do amend NEC for non dwelling use of NM cable so check with local rules as well.
 
iwire said:
You would not be competive here, cable is the norm here.

Up until the 2002 NEC we used NM a lot in commecial occupancies and while still allowed in MA MC is more common.

We commonly use MC for circuits from 2 to 200 amps and sometimes more.
Click to expand...

EMT can be run on the upper end of competitively factoring in value of future expansion, granted you need skilled JW's that have years in pipe bending and proper tooling. Especially when EMT can be used as the ECG which saves on make up.
People are fastest at what they know too.
 
iwire said:
You would not be competive here, cable is the norm here.

Up until the 2002 NEC we used NM a lot in commecial occupancies and while still allowed in MA MC is more common.

We commonly use MC for circuits from 2 to 200 amps and sometimes more.
Click to expand...

What about Marijuana grow spaces which use suspended LED luminaires??? Has NEC weighed in on these????
 
tortuga said:
EMT can be run on the upper end of competitively factoring in value of future expansion, granted you need skilled JW's that have years in pipe bending and proper tooling. Especially when EMT can be used as the ECG which saves on make up.
People are fastest at what they know too.
Click to expand...

Your JWs that have years of pipe bending experience would be competing against JWs with years of experience installing cables quickly. As you said "People are fastest at what they know too."

You would not be competitive, most of out jobs are designed with EMT and that is value engineered out during bidding.
 
dionysius said:
What about Marijuana grow spaces which use suspended LED luminaires??? Has NEC weighed in on these????
Click to expand...
Yes, in 400.7.

Use flexible cord between a junction box and the luminaire - regardless of what the wiring method is supplying the junction box.
 
kwired said:
Yes, in 400.7.

Use flexible cord between a junction box and the luminaire - regardless of what the wiring method is supplying the junction box.
Click to expand...

Seems like following should comply per Table 400.7 :

Trade Name: Hard Service Cord
Type Letter: SO

Is code mandatory on need for receptacle/plug to connect to J-Box or can one use bushing and wire nuts in J-Box based on mainly stationary suspended luminaire that is never moved?? It is not considered wet location per many references and posts.

2nd method (wire nuts/bushing) is less expensive in parts and less labor.
 
dionysius said:
Seems like following should comply per Table 400.7 :

Trade Name: Hard Service Cord
Type Letter: SO

Is code mandatory on need for receptacle/plug to connect to J-Box or can one use bushing and wire nuts in J-Box based on mainly stationary suspended luminaire that is never moved?? It is not considered wet location per many references and posts.

2nd method (wire nuts/bushing) is less expensive in parts and less labor.
Click to expand...
But it is moved (sounds like primarily up/down), that is one thing in 400.7 that makes flexible cord acceptable for this application.

Proper strain relief once flexible cord is allowable is a separate issue, but is more of an AHJ discretion then something specific in the NEC.
 
kwired said:
But it is moved (sounds like primarily up/down), that is one thing in 400.7 that makes flexible cord acceptable for this application.

Proper strain relief once flexible cord is allowable is a separate issue, but is more of an AHJ discretion then something specific in the NEC.
Click to expand...

Thanks. This is where if you get on the wrong side of a less that totally confident Inspector it becomes impossible to win. The movement of these luminaires is more planned, infrequent, and by trained persons. Not quite the same as an extension cord in a domestic or carnival application. Probably depends on the maturity of the Inspector to properly evaluate. There is massive latitude in the interpretation of the words. One is talking multi-million dollars of investment to stand up a few thou sq ft of grow space with HVAC, security, FS, etc. etc.

Is it advisable to take the time to discuss in detail and get prior-approval before forging ahead????? Politically what is the best way to prevail??? And then what if that Inspector is not the one who shows up at inspection time (he may have retired) ???? We are talking 400 such luminaires at circa $1300 each.
 
Last edited:
dionysius said:
Thanks. This is where if you get on the wrong side of a less that totally confident Inspector it becomes impossible to win. The movement of these luminaires is more planned, infrequent, and by trained persons. Not quite the same as an extension cord in a domestic or carnival application. Probably depends on the maturity of the Inspector to properly evaluate. There is massive latitude in the interpretation of the words. One is talking multi-million dollars of investment to stand up a few thou sq ft of grow space with HVAC, security, FS, etc. etc.

Is it advisable to take the time to discuss in detail and get prior-approval before forging ahead????? Politically what is the best way to prevail??? And then what if that Inspector is not the one who shows up at inspection time (he may have retired) ???? We are talking 400 such luminaires at circa $1300 each.
Click to expand...
This is where you better make sure your understanding of code is valid and make sure there is no local amendments that effect what you are trying to do. Then you go over the inspector to his supervisor if need be.

400.7(A)(9) just says "connection of moving parts". Nothing too specific about that at all, but if the luminaires in question get raised and lowered on a regular basis - how does one disqualify this section from applying other then playing the AHJ discretion card?

Nothing in 400.8 has been mentioned yet which could disqualify the use of flexible cord.
 
Status
Not open for further replies.
Top