In a Jam Here..

[Alwayslearningelec]

So have a job we were awarded that the spec indicates MC cable is allowed in walls only.
We figured it in the ceiling( which are hung and accessible)as well but thinking may be on the hook to run conduit in ceiling.
I'm writing an RFI to GC/engineer( begging lol..jk) indicating we figuring MC cable in all concealed locations but I feel he is going to come back and reference spec and say walls only.

Anything I can add to the RFI to sway the engineer to allow MC in ceiling as well, from an electrical standpoint? I can't think of anything such as transitioning from EMT to MC is not good( doesn't make sense), etc. etc.

Thanks.

 

[gadfly56]

So have a job we were awarded that the spec indicates MC cable is allowed in walls only.
We figured it in the ceiling( which are hung and accessible)as well but thinking may be on the hook to run conduit in ceiling.
I'm writing an RFI to GC/engineer( begging lol..jk) indicating we figuring MC cable in all concealed locations but I feel he is going to come back and reference spec and say walls only.

Anything I can add to the RFI to sway the engineer to allow MC in ceiling as well, from an electrical standpoint? I can't think of anything such as transitioning from EMT to MC is not good( doesn't make sense), etc. etc.

Thanks.

Does the spec actually call for EMT or other solid metal raceway in the ceiling, or is this someone's off-hand comment? This is why you read the specs before you put in the bid. Just be aware, if it comes back you're allowed to use MC when EMT is called for, the GC/engineer will absolutely be expecting a price reduction for the "savings" in material and labor.

 

[Alwayslearningelec]

Does the spec actually call for EMT or other solid metal raceway in the ceiling, or is this someone's off-hand comment? This is why you read the specs before you put in the bid. Just be aware, if it comes back you're allowed to use MC when EMT is called for, the GC/engineer will absolutely be expecting a price reduction for the "savings" in material and labor.

I understand. We qualified out letter to the GC that MC was figured in all concealed locations.
What I'm asking for is a electrical reason why it wouldn't make sense to use MC cable in walls and EMT in ceilings. Need to sway engineer.

 

[gadfly56]

I understand. We qualified out letter to the GC that MC was figured in all concealed locations.
What I'm asking for is a electrical reason why it wouldn't make sense to use MC cable in walls and EMT in ceilings. Need to sway engineer.

Sadly, I can't think of any reason that it would be unfavorable, electrically, to put MC in the wall and EMT in the ceiling.

If you qualified your quote in a cover letter that all concealed locations were MC, you might have a chance at a change order to make up the difference. I know we get requests from EC's all the time for a 2-day turnaround on a voice system in a 6-story building or some such similar. You don't have time to see where all the "i's" are dotted and the "t's" are crossed. Usually, we decline to quote.

 

[infinity]

So have a job we were awarded that the spec indicates MC cable is allowed in walls only.

What is the exact wording that they used to describe this installation? Are you supposed to transition to EMT in the wall? Sounds to me like you would stub up the first outlet in EMT and then run from outlet to outlet within the wall with MC cable.

 

[augie47]

I',m having a bit of a problem from the wording in the original post where you state "ceiling( which are hung and accessible)" and then say you instaleld MC in the concealed locations. If the area above the ceiling is accessible, the wiring would not be concealed.

 

[Another C10]

Id say if you gave an itemized breakdown during the estimate clearly stating your design intentions, you should be good.
If you simply said x amount of dollars as per spec then your reputation is on the line.
If you didn't collect a deposit Id think your not obligated to accommodate the agreement, things happen, plans change, most General Contractors would honor that, although you may be blacklisted. It's always a good idea to itemize all applications and use brief descriptions of the intention regarding any installations.. Like all branch wiring switch legs and power systems to be MC and all home runs from panels to be EMT.

Good luck on that one.

 

[synchro]

Are there any amendments where the job is located pertaining to the use of MC?
For example, in Chicago the following is under article 330 for Type MC:

 

[petersonra]

I don't know what the point of allowing MC in walls and not above ceilings is.

 

[petersonra]

I',m having a bit of a problem from the wording in the original post where you state "ceiling( which are hung and accessible)" and then say you instaleld MC in the concealed locations. If the area above the ceiling is accessible, the wiring would not be concealed.

Concealed. Rendered inaccessible by the structure or finish of
the building.

Accessible (as applied to wiring methods). Capable of being
removed or exposed without damaging the building structure
or finish or not permanently closed in by the structure or finish
of the building.

Exposed (as applied to wiring methods). On or attached to the
surface or behind panels designed to allow access.

Kind of a close call, but I am inclined to agree with your assessment.

 

[synchro]

I don't know what the point of allowing MC in walls and not above ceilings is.

MC is allowed to be fished above existing hard surfaced ceilings as well as in existing walls. In the OP's case where the ceiling is removable for access, MC would not be allowed.

 

[petersonra]

MC is allowed to be fished above existing hard surfaced ceilings as well as in existing walls. In the OP's case where the ceiling is removable for access, MC would not be allowed.

I tend to agree fishing it would be inappropriate above the ceiling but attaching it to the surface above the drop ceiling would seem to be acceptable to the code.

 

[JoeStillman]

MC above ceilings needs to be supported independently of the ACT. You need extra hanger wires.

 

[infinity]

I tend to agree fishing it would be inappropriate above the ceiling but attaching it to the surface above the drop ceiling would seem to be acceptable to the code.

Yes MC cable is run above hung ceilings all of the time. Not sure why this particular spec is against that. As I said prior I would just stub up from the first outlet with EMT and run MC cable within the walls from there.

 

[roger]

I have been on a project where this spec was used and after asking what sense it would make to use an unforgiving wiring method in concealed spaces and use EMT that you can always pull conductors into in an accessible space the response was "because".

 

[steve66]

I don't know what the point of allowing MC in walls and not above ceilings is.

I have been on a project where this spec was used and after asking what sense it would make to use an unforgiving wiring method in concealed spaces and use EMT that you can always pull conductors into in an accessible space the response was "because".

In my opinion, not having a mess of spaghetti above the ceiling counts for something. It also makes things much neater back at the panel. And if an additional branch circuit needs to be added, it can often be pulled into an existing conduit for most of the run, instead of having to add MC cable for the entire run.

And having one 3/4" conduit with a full boat doesn't seem like it would cost that much more than running 3 MC cables.

Id say if you gave an itemized breakdown during the estimate clearly stating your design intentions, you should be good.
If you simply said x amount of dollars as per spec then your reputation is on the line.
If you didn't collect a deposit Id think your not obligated to accommodate the agreement, things happen, plans change, most General Contractors would honor that, although you may be blacklisted. It's always a good idea to itemize all applications and use brief descriptions of the intention regarding any installations.. Like all branch wiring switch legs and power systems to be MC and all home runs from panels to be EMT.

Good luck on that one.

Not sure how it is on residential projects, but on commercial projects a bid is a bid. And they are normally backed up with a bid bond that guarantees the work will be performed for the price bid.

Once had a supplier that missed an elevator on a project (they counted 2 instead of 3, or something like that.) They wound up eating the cost of an elevator.

 

[roger]

In my opinion, not having a mess of spaghetti above the ceiling counts for something. It also makes things much neater back at the panel. And if an additional branch circuit needs to be added, it can often be pulled into an existing conduit for most of the run, instead of having to add MC cable for the entire run.

If run correctly it would not look like spaghetti. Pulling into an existing conduit was the point I was making in conduit or tubing being a forgiving wiring method.

And having one 3/4" conduit with a full boat doesn't seem like it would cost that much more than running 3 MC cables.

It would probably be less expensive to run conduit.

Not sure how it is on residential projects, but on commercial projects a bid is a bid. And they are normally backed up with a bid bond that guarantees the work will be performed for the price bid.

Yeah, residential is no where near the bid and specification process that commercial is.

Once had a supplier that missed an elevator on a project (they counted 2 instead of 3, or something like that.) They wound up eating the cost of an elevator.

Ouch!!!.

 

[Another C10]

I tend to agree fishing it would be inappropriate above the ceiling but attaching it to the surface above the drop ceiling would seem to be acceptable to the code.

Its legal here, although attaching MC above the T bar needs to be attached to the electrical Tye wire, like for the troffers supports, not usually allowed on any ol T Bar grid wire. 3/8" Caddy clips are a common method of attachment usually every 4ft.

 

[Another C10]

Yeah, residential is no where near the bid and specification process that commercial is.

new commercial is a whole other level of guidelines and requirement much larger dollars too as well as much larger profit of loss.
I'll stick to the small stuff, my ego won't mind.

 

[Another C10]

And having one 3/4" conduit with a full boat doesn't seem like it would cost that much more than running 3 MC cables.

They do make 3 phase MC 5 conductor