Unsecured box/receptacle...

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c_picard

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Good evening,
I just received a sketch from the architect/engineer for 120v receptacles to be installed under a raised floor assembly. Here's the catch; We are to install a
4"x4" trough right down the center of the underfloor space, then come out of the trough with 20' lengths of MC with a receptacle mounted in a Handy box at the end. It seems there intention is to be able to move the receptacles to where power is needed, but a few code issues come to mind. The box needs to be secured, no? The MC needs to be secured and supported. Hard usage cord with strain relief and a pendant style box seems more appropriate. Any input?
Thanks people...
Charles
 
Article 645 or not that wiring method is required to be secured.

There are no exceptions that allow you to 'float' MC or handy boxes under a raised floor.

Further the fact they specified "Handy Boxes" only shows their lack of real experience.

Installing a commercial grade receptacle in a handy box is IMO a bad plan.

At the least a single gang FS style box or a 4: square with a raised duplex cover should be used.

Using 4" x 4" trough is also an indicator of no hands on experience, working in a 4" x 4" trough is a pain. Left up to me I use a 6" x 6" minimum.

But I would not run trough in the first place for this type of job.

EMT or MC right back to the panel would be my choice.
 
iwire said:
Article 645 or not that wiring method is required to be secured.

There are no exceptions that allow you to 'float' MC or handy boxes under a raised floor.

.
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I am confused. What else is new....According to article 645.5(D)(2) it states clearly that you cannot use mc cable without securing it, yet 645.5 (E) gives a different impression. My question is what power cables are they talking about in (E)
 
Dennis Alwon said:
According to article 645.5(D)(2) it states clearly that you cannot use mc cable without securing it,
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That is correct.

yet 645.5 (E) gives a different impression. My question is what power cables are they talking about in (E)
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'E' is referencing power cables that 'are listed as part of, or listed for information technology equipment'

MC is not specifically listed for information technology equipment.

What 'E' does cover is Assemblies that are specifically listed for that use.

In my experience these Assemblies are typically available from the manufacturers of the PDUs (Power Distribution Units) A fancy name for what is usually a single large enclosure containing a 480 Delta to 208Y/120 transformer and one or more panels.

These assemblies are often simply prewired liquid tight with FS style boxes on one end containing the specified receptacle and the other end with just a connector to enter it into the PDU.
 
Thanks Bob, I appreciate the response. Another question--- the OP asked about hard usage cord and plug. Although it is mentioned in 645.5(B) It is not listed in 645.5 (D)-- The answer would be then "NO" to his suggestion????
 
c_picard said:
Hard usage cord with strain relief and a pendant style box seems more appropriate. Any input?
Thanks people...
Charles
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No on the cord unless the room meets all the 645 requirements and the cord is listed as "Type DP"

IMO there are two choices.

Use standard wiring methods. (Secured, MC, EMT, Rigid etc.)

or if they insist on 'floating' the boxes and wiring

If it is a 645 room buy premade listed power whips from an Information Technology equipment supplier.
 
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iwire said:
If it is a 645 room buy premade listed power whips from an Information Technology equipment supplier.
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One of our major customers has their in-house electricians making up these whips using the "computer room sealtight" (I forgot the exact designation) with bell boxes on the end. Is this legit?
 
peter d said:
their in-house electricians making up these whips using the "computer room sealtight" (I forgot the exact designation) with bell boxes on the end. Is this legit?
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Is it to be expected?

Or is it legit?

IMO it can not be done in house.....although I think it can be done just as well.
 
peter d said:
One of our major customers has their in-house electricians making up these whips using the "computer room sealtight" (I forgot the exact designation) with bell boxes on the end. Is this legit?
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Hello Peter.

This would be fine but they must still be secured per 300.11.

Roger
 
When you say "secured", does this mean it is ok to tie wrap the mc to pipe, as long as it is tie wrapped within every 6' and 12" of every box?
 
NYC Elect said:
When you say "secured", does this mean it is ok to tie wrap the mc to pipe, as long as it is tie wrapped within every 6' and 12" of every box?
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IMO cable ties are fine, assuming the pipe you are talking about is not conduit or some other mechanical piping that may prohibit it's use as a support.

Roger
 
Im sorry...The pipe I was talking about is a 3/4" emt run under the raised floor. The emt is secured correctly, but, does this mean it is ok to secure the mc to it?
 
NYC Elect said:
Im sorry...The pipe I was talking about is a 3/4" emt run under the raised floor. The emt is secured correctly, but, does this mean it is ok to secure the mc to it?
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No, you can not use EMT that is in use as a raceway to secure cables.

I typically secure the MC or LFMC to the raised floors legs every 2' with either tie wraps or bailing wire.
 
NYC, see 300.11(B), your scenario will not be applicable.

Roger
 
If the wiring is 12 AWG, then the handy box would not fulfill the box fill requirements.


If there is an EC filing this work, and the house electricians are doing work, I as the EC would specifically write on my application and have the inspection company write in their certificate that the work performed by others is not their responsibility. See where that leads to ;)
 
Thanks for the input.
This raised floor is not located in a 645.- room. It is to be used as a training room, which may or may not be reconfigured at a later time. I think I'll voice my concerns to the architect and engineer, and if they can't come up with something code compliant I will install the MC and surface mounted receptacles in a code compliant manner(..secured and supported). I don't feel it should be my job to decipher the intentions of the engineer. If they explicitly say that they need have the receptacles moveable, there should be some added cost to this install. If in house personnel comes in after the fact and removes the supports, am I at all liable?
 
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