Plastic Boxes on Commercial Jobs

ngd4130

Member
I need to pick some brains. This question is straight forward.
Are plastic boxes (of any style or manufacturer) allowed to be used on a commercial job??
In my case, it is a four-story hotel. Romex (NM) cable has already been approved per the drawings but the spec book says metal boxes only.
Is there a Building Code or NEC code that is specific to the use or non-use of plastic boxes??
Inspector 007
 

kwired

Electron manager
Location
NE Nebraska
I need to pick some brains. This question is straight forward.
Are plastic boxes (of any style or manufacturer) allowed to be used on a commercial job??
In my case, it is a four-story hotel. Romex (NM) cable has already been approved per the drawings but the spec book says metal boxes only.
Is there a Building Code or NEC code that is specific to the use or non-use of plastic boxes??
Inspector 007
Other then not following the specification- not really. If NM cable is permitted then a plastic box will normally be permitted.

Situations that won't allow a plastic box typically won't allow NM cable to be used either.

Fire rating of a finish may not allow certain plastic boxes but doesn't automatically prohibit all of them, see rating of the box in question in those cases.
 

69gp

Senior Member
Location
MA
I need to pick some brains. This question is straight forward.
Are plastic boxes (of any style or manufacturer) allowed to be used on a commercial job??
In my case, it is a four-story hotel. Romex (NM) cable has already been approved per the drawings but the spec book says metal boxes only.
Is there a Building Code or NEC code that is specific to the use or non-use of plastic boxes??
Inspector 007

Plastic may be allowed by code but that does not apply in this situation. If the engineer specified metal boxes there is a reason for it. Most likely metal boxes are more durable and the screw holes for mounting the device will stand up better overtime.

best advice i can give is ask the question.

Can plastic boxes be used in lieu of metal boxes?


i would hate to see you rough in 2 floors with sheet rock going up when the engineer does a walk through and bags you on using plastic boxes.
 

tkb

Senior Member
Location
MA
If the job was specified with metal boxes, and you used plastic boxes, the customer is within their rights to receive a credit for this change.

That is if they accept the change and don't make you remove the plastic boxes and replace with metal.

Do you feel lucky, we'll do you?
 

ngd4130

Member
i would hate to see you rough in 2 floors with sheet rock going up when the engineer does a walk through and bags you on using plastic boxes.
Good thing for me - I am the inspector. Bad thing for contractor since it is already spec'd out for metal boxes.
 

James L

Senior Member
Plastic may be allowed by code but that does not apply in this situation. If the engineer specified metal boxes there is a reason for it....
from what I've seen, most engineers spec only what they're familiar with, and don't really have any "why" behind it.

I would probably look at the context in which it's spec'd. Just in the general notes, something like "boxes to be 4-inch square with 5/8" plaster ring...yada yada"

If so, it really amounts to nothing but stock "filler" jargon
 

iwire

Moderator
Staff member
Location
Massachusetts
from what I've seen, most engineers spec only what they're familiar with, and don't really have any "why" behind it.

I would probably look at the context in which it's spec'd. Just in the general notes, something like "boxes to be 4-inch square with 5/8" plaster ring...yada yada"

If so, it really amounts to nothing but stock "filler" jargon
Yes but if the contract references that stock filler you either provided it or be prepared to give a credit.
 

69gp

Senior Member
Location
MA
from what I've seen, most engineers spec only what they're familiar with, and don't really have any "why" behind it.

I would probably look at the context in which it's spec'd. Just in the general notes, something like "boxes to be 4-inch square with 5/8" plaster ring...yada yada"

If so, it really amounts to nothing but stock "filler" jargon

That is why I say to ask the question to the engineer. If they allow the substitution then the owner has the right to ask for a credit. I would say that $3 per box would do.
 

tkb

Senior Member
Location
MA
I know some contractors that could turn a change from metal boxes to plastic boxes into a change order for more and not a credit.
 

69gp

Senior Member
Location
MA
Good thing for me - I am the inspector. Bad thing for contractor since it is already spec'd out for metal boxes.

Just curious if you are the municipal inspector or are you working for the owner / engineer. I only ask this for the following reason.

If you are a municipal inspector are you required to inspect to what the engineer requires or just what the NEC requires for a minimum?


If you are working for the owner as a 3rd party inspector I can see where you have the right to require the metal boxes.


It would be like saying the specs called for all EMT to be used. But the installing contractor decided to change it to romex because its allowed by code. They both meet code if properly installed.


I do a lot of 3rd party inspections and see this done all the time. Contractors cutting corners. When they get caught its always this excuse or that.


The way I explain it is like this.

You go and order a new caddy fully loaded. Cost you $60,000. Dealer say it will be in in 6 weeks. Boom, you get a call car is in. You go to pick it up and its Nissan Versa $13,000. Both have AC, windows that open and it gets you from point A to point B. What would you say?

 

kwired

Electron manager
Location
NE Nebraska
Good thing for me - I am the inspector. Bad thing for contractor since it is already spec'd out for metal boxes.
I guess how it impacts you as the inspector depends if you are supposed to inspect for compliance with the designer's spec's, or if you are just supposed to make sure it is code compliant.
 

GoldDigger

Moderator
Staff member
I guess how it impacts you as the inspector depends if you are supposed to inspect for compliance with the designer's spec's, or if you are just supposed to make sure it is code compliant.
I imagine part of that would depend on what was called out on the possibly approved plans rather than just in the contract.
 

kwired

Electron manager
Location
NE Nebraska
I imagine part of that would depend on what was called out on the possibly approved plans rather than just in the contract.
Sort of what I was trying to say. Some places they inspect not only for code compliance but for compliance with the plans.

Here I have never showed an inspector any plans or specifications that I can recall, if NEC compliance is met that is all they care about, if the owner or designer wants to know if you followed the specifications or plans it is up to them how to determine if that has happened.

I guess the inspection department can raise their fees and check specifications.
 

ADub

Senior Member
Location
Iowa
Every job I've ever worked on in the commercial and institutional sector had an electrical inspection for nec compliance and a separate site walkthrough and final sign off by the architectural firm based on plan conformity. Neither party could or would do the other party's inspection


Sent from my iPad using Tapatalk
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Good thing for me - I am the inspector.
Depends on how you look at it; if you would like to spend the next three days combing through the GC's trailer looking for the one sentence that deleted the metal boxes out of the specs, and you feel that's your job and a valuable use of taxpayer money, knock yourself out.

Or, you can inspect according to the NEC and keep out of it.
 

Strathead

Senior Member
Good thing for me - I am the inspector. Bad thing for contractor since it is already spec'd out for metal boxes.
Please respond back and answer whether you are a municipal inspector or a private, or institutional inspector for us. I am curious whether you have the "right" to inspect to specification instead of code. Since it is a job where romex has been accepted, I am guessing you are a city or county inspector and your job is to ensure code compliance. If your question was asking if there was an application where romex is allowed by code, but plastic boxes aren't I believe the answer is no.
 

Strathead

Senior Member
That is why I say to ask the question to the engineer. If they allow the substitution then the owner has the right to ask for a credit. I would say that $3 per box would do.
Then you don't want to be in the electrical business do you? The OP isn't a contractor but instead an inspector, so the credit issue doesn't apply to him, but having been involved in many, many projects that have been value engineered and/or have specs that aren't compatible with each other, I can think of a dozen valid arguments right off the top of my head on how I would fight a request for a credit for plastic boxes. It very much depends on the situation. There is just no valid reason to require metal boxes with NM cable. If you are going cheap, then go cheap. Engineers are subject to the same problems the rest of us are. They have boilerplate specs, and they don't get paid enough to go through every item of a spec and make sure that it is perfect, so they miss things like this when a job is outside their normal spec wheel house. As an estimator it should be picked up an and at least clarified in the bid, but sometimes the estimator is under the same constraint.

It is extremely unlikely that I would give back a credit for this on a job I estimated and ran. I have spent years honing the skill of identifying counter arguments. One of the best ones is that you always pay attention to the little things you do because you know they must be done even though the plans don't indicate it properly. Like when they show hash marks on a plan and the number of wires is wrong. You don't pull the wrong number of wires, you just do it. That becomes very handy when you explain that you didn't install (or price) metal boxes when plastic was in line with the intent of the drawings, you just did it.
 
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