- Location
- Massachusetts
I see no reason to change the code, the simple answer is to have the HVAC contractor provide the correct hardwired type of pump.
I see no reason to change the code, the simple answer is to have the HVAC contractor provide the correct hardwired type of pump.
agreed, it's not a big deal.I see no reason to change the code, the simple answer is to have the HVAC contractor provide the correct hardwired type of pump.
I see no reason to change the code, the simple answer is to have the HVAC contractor provide the correct hardwired type of pump.
Next code change: " ... and 250v receptacles ... "Just think how the GFI issues would change for us if all Commercial Kitchen equipment was 240v instead of 120v.
I see no reason to change the code, the simple answer is to have the HVAC contractor provide the correct hardwired type of pump.
Bob I would ordinarily agree with you 100%, but I don't see how the Code can prohibit flex cords above a grid ceiling (which is fairly easy to access and is dryer and often cleaner than underfloor spaces) and yet allow them below a raised floor where I have personally seen excess moisture, dirt and other junk built up. It just doesn't make any sense to me.
When was the last time someone flooded a grid ceiling or spilled a mop bucket up there? :grin:
Now if the grid ceiling is a plenum space, (which is rare but does happen) I can see a concern for possible smoke and/or flame contribution issues. Again ironic since a lot of raised floors (especially in data centers) are used as air circulation space.
If it is NOT a plenum ceiling I see no reason for the prohibition.
Bob I would ordinarily agree with you 100%,
but I don't see how the Code can prohibit flex cords above a grid ceiling (which is fairly easy to access and is dryer and often cleaner than underfloor spaces) and yet allow them below a raised floor
where I have personally seen excess moisture, dirt and other junk built up.
It just doesn't make any sense to me.
When was the last time someone flooded a grid ceiling or spilled a mop bucket up there? :grin:
Now if the grid ceiling is a plenum space, (which is rare but does happen) I can see a concern for possible smoke and/or flame contribution issues. Again ironic since a lot of raised floors (especially in data centers) are used as air circulation space.
If it is NOT a plenum ceiling I see no reason for the prohibition.
I don't see a reason even if it is a plenum ceiling. Keep in mind the entire occupied space is also a plenum, how many cords are in that space?
Why is it our 'NEMA' cords do not perform this well?
Next code change: " ... and 250v receptacles ... "
I pretend to be an engineer, not an electrician, but to me, a significant issue is that heat (and smoke) rises ... damage under a floor will be more likely to make itself known than above the dropped ceiling.Bob I would ordinarily agree with you 100%, but I don't see how the Code can prohibit flex cords above a grid ceiling (which is fairly easy to access and is dryer and often cleaner than underfloor spaces) and yet allow them below a raised floor where I have personally seen excess moisture, dirt and other junk built up. It just doesn't make any sense to me.
No, ordinarily we do not agree.
The same code section that prohibits cords above ceilings also prohibits cords below floors. Or did you not really look at the code sections?
Article 645 allows certain types of cords below floors but in order to use 645 you need to conform to all the rules found in 645.4 EPO button, seperate HVAC and or smoke dampers, room occupied by only necessary people, the room separated from other areas by fire resistant walls floors and ceilings.
I have never seen an above ceiling space with an EPO button.
I do not think the rule has anything to do with 'moisture, dirt and other junk'.
That seems to be a running theme with you. :grin:
Yeah lets forget that there is no reason we have to use cords above ceilings, there are other wiring methods including flexible ones. To me the fact that the cords covered by the NEC will degrade, crack and have the installation fall off them, which I have seen it first hand more than once is enough reason to keep the prohibition as it is.
Side note. I used to work on some German made equipment that was exclusively wired with a European type flexible cord, these cords where left outside at an ocean front continuously for at least 25 years before I worked with them. A lot of the cord was also in full sun, they where still in great shape, stiffer but not cracking. Where I stripped them for cord connector replacement the internal insulation and conductors looked brand new. Why is it our 'NEMA' cords do not perform this well?
iwire said:Actually the space above a ceiling is never a 'plenum' and neither is the entire space.
There are several architects and engineers who will disagree with the first part of that statement (in bold). My new screening room's projection booth ceiling is classified as a plenum ceiling and ALL of the LV wiring for my sound system in that space had to be in conduit or be plenum rated. :grin:
Now having 645 makes more sense in why it allows IT rooms to have cords, but it still doen't change my opinion on the wisdom based on my comment about "moisture, dirt and other junk."
Perhaps you are right..you have seen a lot of bad cords in that environment, but in the situations I have run into (usually things like ceiling-mounted video projectors for example) I have yet to see a cord even stiffer than normal. I imagine it would greatly depend on the "environment" above the ceiling as well as quality of cord and its age.
By the same token I have seen damaged/corroded MC cable above ceilings as well.
There is simply no such thing as a perfect wiring method no matter what you use it for.
Is any kind of aging test a part of NEMA standards?
There are several architects and engineers who will disagree with the first part of that statement (in bold). My new screening room's projection booth ceiling is classified as a plenum ceiling and ALL of the LV wiring for my sound system in that space had to be in conduit or be plenum rated. :grin:
Bob I would ordinarily agree with you 100%, but I don't see how the Code can prohibit flex cords above a grid ceiling (which is fairly easy to access and is dryer and often cleaner than underfloor spaces) and yet allow them below a raised floor where I have personally seen excess moisture, dirt and other junk built up. It just doesn't make any sense to me.
When was the last time someone flooded a grid ceiling or spilled a mop bucket up there? :grin:
Now if the grid ceiling is a plenum space, (which is rare but does happen) I can see a concern for possible smoke and/or flame contribution issues. Again ironic since a lot of raised floors (especially in data centers) are used as air circulation space.
If it is NOT a plenum ceiling I see no reason for the prohibition.
I'll have to do some research on this, but I have a feeling that 400.8.5 wasn't intended for a piece of equipment with a listed cord plugged in, but rather prohibit running cords as branch wiring.
No, ordinarily we do not agree.
Side note. I used to work on some German made equipment that was exclusively wired with a European type flexible cord, these cords where left outside at an ocean front continuously for at least 25 years before I worked with them. A lot of the cord was also in full sun, they where still in great shape, stiffer but not cracking. Where I stripped them for cord connector replacement the internal insulation and conductors looked brand new. Why is it our 'NEMA' cords do not perform this well?
I'll have to do some research on this, but I have a feeling that 400.8.5 wasn't intended for a piece of equipment with a listed cord plugged in, but rather prohibit running cords as branch wiring.