Repair Garage Wiring

[goldstar]

Is it permissible to use NM cable above a suspended ceiling in the waiting room areas of repair garages ? All walls are sheet-rocked and ceiling areas are accessible. Existing wiring was done in either EMT or MC cable but was done while walls were open. Garage is being renovated with new lifts, etc but the showroom area is not.

I'm sure I know the answer to this but just asking in case I missed something in some obscure code somewhere.

Tnx.

 

[Leespark57]

No. See 334.12(A)(2)

 

[Ponchik]

Without looking into the book, I think the only place you can use NM cable above the mentioned ceiling is residential.

 

[goldstar]

Without looking into the book, I think the only place you can use NM cable above the mentioned ceiling is residential.

I don’t believe that is correct. It can be used in office spaces of commercial buildings that are less than 3 stories. I guess my question is “Does the entire building qualify as being a repair garage even if block walls separate the actual garage from the waiting area”?

I don’t have my Code book available at the moment so I haven’t had time to reference that code section.

 

[infinity]

I don’t believe that is correct. It can be used in office spaces of commercial buildings that are less than 3 stories. I guess my question is “Does the entire building qualify as being a repair garage even if block walls separate the actual garage from the waiting area”?

I don’t have my Code book available at the moment so I haven’t had time to reference that code section.

The 3 story rule has been out if the NEC for years. NM is not permitted above hung ceilings in anything but residential. NJ does have an exception to this rule.

 

[goldstar]

The 3 story rule has been out if the NEC for years. NM is not permitted above hung ceilings in anything but residential. NJ does have an exception to this rule.

Thanks. I’m glad you brought that to my attention. Why didn’t I learn that in a CEU class ?

I recently replaced about 10 troffers in an office space that had NM cable to all the fixtures. I’m guessing that was grandfathered in.

 

[jap]

Or the original installer didn't know any better to begin with.

JAP>

 

[Ponchik]

Thanks. I’m glad you brought that to my attention. Why didn’t I learn that in a CEU class ?

I recently replaced about 10 troffers in an office space that had NM cable to all the fixtures. I’m guessing that was grandfathered in.

Or maybe it was never inspected.

 

[rcarroll]

NM was allowed above a commercial dropped ceiling until 2002.

 

[infinity]

Thanks. I’m glad you brought that to my attention. Why didn’t I learn that in a CEU class ?

Here's the NJ amendment:

4. Chapter 3 of the electrical subcode, entitled "Wiring Methods and Materials," is amended as follows:

i. Section 300.4(A)(1) is amended to delete the words from "so that the edge. . ." on line four through ". . . cannot be maintained" on line six and in lieu thereof substitute "as required by the building subcode. Where the distance from the edge of the hole to the nearest edge of the wood member is less than 32 mm (1 1/4 inches)."
ii. Section 334.12(A)(2) is deleted in its entirety.

 

[jumper]

NM was allowed above a commercial dropped ceiling until 2002.

Yep, the NEC got rid of the height limit and added the restriction for for above non resi drop ceilings IIRC.

 

[tom baker]

Thanks. I’m glad you brought that to my attention. Why didn’t I learn that in a CEU class ?

I recently replaced about 10 troffers in an office space that had NM cable to all the fixtures. I’m guessing that was grandfathered in.

It was about 2002...

 

[goldstar]

This is kind of a sad commentary on my behalf. I generally have about 60 CEU credit hours racked up over the course of a 3-year period and I don't remember this code change. Certainly a teachable moment for me. Anybody have that crow recipe available ?

As luck would have it we had an exec board meeting last night for our contractors association and I brought this topic up. Only myself and one other out of the six of us was aware of this code change. Perhaps we need a new CEU instructor.

 

[Cavie]

When the code changes, buy a book of only code changes and read it.

 

[goldstar]

When the code changes, buy a book of only code changes and read it.

I have them all from 1993 when I got my license. This one just got by me. I guess it’s because I don’t do a lot of new commercial work. Just maintenance and small add-ons at small strip malls and office bldgs. Somehow it just didn’t stick in my head

 

[kwired]

Nearly every CEU I have ever attended that focuses on changes to the most recent code typically uses slideshow produced by a well known organization such as IAEI, Mike Holt, etc. They usually start at the front end of code and catch every change no matter how slight it may be.

We are usually lucky to see any of the changes past chapter 4 as the time of the CEU is usually up before we ever get that far. Some instructors will try to get through chapter 3 one slide at a time then start to skip to significant changes that they think will be more interest to the class, or even ask if there is anything anybody wants to make sure they cover in the class, but when it comes to changes you need to know there is a change to ask to discuss it, so it would have to be a situation where you know of the change but want more input on peoples opinions/interpretations of the change.

 

[goldstar]

I’m sure this was in Mike Holt’s Code Changes book at that specific time interval but somehow it didn’t stand out for me. You know the way these Code changes come about - thers’s usually a “change in language”. There isn’t a preamble that states ”Hey, you’re no longer allowed to do this”. It’s generally up to the people like Mike Holt’s crew who write the Code changes books to pick up on this and bring it to our attention. This one just didn’t sink in for me.

Just goes to show - You have to pay for your education.:thumbsup:

 

[kwired]

I’m sure this was in Mike Holt’s Code Changes book at that specific time interval but somehow it didn’t stand out for me. You know the way these Code changes come about - thers’s usually a “change in language”. There isn’t a preamble that states ”Hey, you’re no longer allowed to do this”. It’s generally up to the people like Mike Holt’s crew who write the Code changes books to pick up on this and bring it to our attention. This one just didn’t sink in for me.

Just goes to show - You have to pay for your education.:thumbsup:

A good CEU instructor picks up on which ones are significant changes to most people and puts more emphasis on those when presenting them. There often is a lot of changes that is just editorial in nature and the main intent of how we wire things really never changed - it is easy to daydream your way through a CEU session when there is a lot of those types of changes being covered.

Then there are those times where careful placement or change of just one or two words changes the entire meaning of what it said before.

250.50 a few cycles back changed "where available" to "are present", and have little or no other changes - but made a big mess of confusion for installers and inspectors everywhere. Not so much that the wording was confusing - it was pretty clear, it just changed what a lot of people had been doing for years.

 

[infinity]

In NJ you have to take 9 hours of classroom instruction every three years just on the code changes. Many CEU instructors use Mike Holt's PowerPoint deck and give out the code changes book.