Question?

[hotline1]

A UL labeled powered HEPA filter unit, 120 volt, designed to be installed in a 2x4 drop ceiling, equipped with a factory 5' cord and molded plug.
Design and intent is for a clean room enviornment.

In a discussion with a local AHJ, the following comments were noted:

Article 408 prohibits cord & plug connections above a drop ceiling.

Cord is prohibited within a plenum rated ceiling.

My question; how can an item have a UL label/listing and be in violation of the NEC, if the item is installed "as equipped" from the factory??

This type of HEPA filter unit is designed to filter air thru a drop ceiling (plenum). It is equipped with an external pre-filter, and the unit has two fractional HP fan motors, and a factory speed control, mounted on the top area of the unit.

Any input will be appreciated.
John

[ March 02, 2003, 10:54 PM: Message edited by: hotline1 ]

 

[dana1028]

Re: Question?

Hotline - I understand your question - our company has 'clean rooms' - there are actually two models of the hepa unit you are referring to.

For the 'drop ceiling', plenum air space above situation we use basically the same hepa you are referring to, except it is not 'cord & plug' - it is connected using flex, MC, etc.

For our 'portable' CERs (Clean rooms), i.e. modular clean rooms - we use the cord & plug hepa (due to the 'mobility' of these clean rooms...they can and do get moved around).

You might want to double check the listing for your particular hepa unit as to its applicability for you 'hard ceiling' situation.

 

[don_resqcapt19]

Re: Question?

dana,
400.8(5) does not permit the cord to be above any type of ceiling, plemumn or not.

John,
Did you try to contact UL with this question?

Don

 

[ron]

Re: Question?

400.8(5) "Where concealed by ...... or located above suspended ceilings or dropped ceilings."
I have struggled with this paragraph, mainly due to the word "concealed" and whether it gets applied to the latter part of the sentence. The definition of "concealed" from Article 100 makes 400.8(5) not apply to a standard suspended 2'x4' or 2'x2' ceiling since a standard suspended ceiling does not conceal (by NEC definition). Does anyone else see this interpretation?

 

[iwire]

Re: Question?

Same Question over here

ECN Forum

I think Websparky has the answer, 400.7(A)(8)

The first sentence in 400.8 "Unless specifically permitted in 400.7"

[ March 04, 2003, 08:22 PM: Message edited by: iwire ]

 

[don_resqcapt19]

Re: Question?

400.8(5) was reworded last code cycle to make it clear that cords are not permitted above the ceiling. In the '99 code there was a problem with the use of the word "concealed" as it did apply to the ceiling and per Article 100 the area above a lay in tile ceiling is not concealed. In the 2002 wording the word concealed does not apply to the ceiling part of the rule. Cords are not to be "located" above a ceiling in the 2002 code. Even CMP 6 was confused about the '99 wording as the proposal to add the word "located" was rejected in the ROP, but after comments made clear the need for the code change the panel accepted the proposal.
Don

 

[hotline1]

Re: Question?

Thank you for the responses!!
It's late in the night, it's been a long day
I printed and will re-read your comments promptly
John

 

[iwire]

Re: Question?

Don, If that is what they want I feel they have more changes to make.

400.7(A)8 mentions appliances that need to be removed for "maintenance and repair"

and "intended or identified for flexible cord use"

I would say a HEPA filter would need service and it came with a UL listing with a cord on it.

408 Uses Not permitted. "Unless specifically permitted in 400.7"