Mike Holt video on art. 400

[Dennis Alwon]

Mike makes a very good point in this almost 10 minute video. The jist of the vid is that art. 400 applies to flexible cords and cables. If you go to Annex A in the back of the NEC you will see that flexible cords and cables has a product standard by UL62. Cord sets and power cords are a different standard as they are UL 817.

What does this mean? It seems that the power cords such as the cords that are part of the listing of a particular piece of equipment is allowed above a drop ceiling assuming it is not a plenum. Power cord sets are the cords such as you would find on a laptop with the power supply in the cord. Power cords are basically extension cords listed for equipment or cords that are direct wired into a piece of equipment and have a male end to get power.

He has a good point and I am curious how the cmp will address this. If art. 400 title was flexible power cords & Cables, power cords and cord sets that would solve the issue.

Any thoughts

https://www.youtube.com/watch?v=Da5SMuqQJ_8&index=15&list=PLRNS1x1jcKbHR6mAChnrfOpmm8NGop6k_

 

[infinity]

I wish someone would come up with a sensible re-write of this section. Besides it's ambiguity, it doesn't make much sense when a piece of equipment used above the ceiling will fail long before its power cord, like a condensate pump. I can see prohibiting someone from running an extension cord above the ceiling but the current version of this section is poorly written as Mike has pointed out.

 

[iwire]

, it doesn't make much sense when a piece of equipment used above the ceiling will fail long before its power cord, like a condensate pump. I can see prohibiting someone from running an extension cord above the ceiling but the current version of this section is poorly written as Mike has pointed out.

On the other hand I see no hardship created by an outright ban on concealed flexible cords. To me that makes more sense then counting on the failure of a pump to happen before the failure of a cord supplying it.

There are hardwired condensate pumps, the HVAC guys just need to get used to using them.

I doubt our local FDs and EIs will see it like Mike sees it.

 

[roger]

I doubt our local FDs and EIs will see it like Mike sees it.

Same here along with myself.

I have seen to many rotted cords (not necessarily above ceilings) to think concealing them is allowed or a good idea.


Roger

 

[Dennis Alwon]

IMO this is not about whether it is a good idea but more about what the code is saying (not necessarily intent). Mike seems to be right on about what is being said in art. 400. Since flexible cords and cables fall under UL 62 then art, 400 as written should not apply to anything other than UL 62 products.

 

[GoldDigger]

Same here along with myself.

I have seen to many rotted cords (not necessarily above ceilings) to think concealing them is allowed or a good idea.


Roger

Have you seen rotted extension cords or rotted power cord sets?
I have seen a lot of rotted two wire rubber insulated lamp cords.
And occasional rotted round vacuum cleaner cords.

 

[iwire]

IMO this is not about whether it is a good idea but more about what the code is saying (not necessarily intent). Mike seems to be right on about what is being said in art. 400. Since flexible cords and cables fall under UL 62 then art, 400 as written should not apply to anything other than UL 62 products.

I understood what this was about.

Yet I still believe that my local AHJs will continue enforcing it as they have before regardless of what Mike is pointing out.

 

[petersonra]

I don't recall ever seeing a rotted cord.

I have seen a few that have minor insulation degradation.

i have seen some that have been damaged.

never seen a rotted one.

and I have been around some cords in some really bad environments.

 

[Dennis Alwon]

I understood what this was about.

Yet I still believe that my local AHJs will continue enforcing it as they have before regardless of what Mike is pointing out.

I have no doubt that that will be true all over the country

 

[Dennis Alwon]

I don't recall ever seeing a rotted cord.

I have seen a few that have minor insulation degradation.

i have seen some that have been damaged.

never seen a rotted one.

and I have been around some cords in some really bad environments.

I have seen some very old rubber cords that were connected to whole house fans in some residential attics. The cords still worked but they were dry rotted from the heat. This would not be the case in a dropped ceiling. I always wondered why it was not allowed but Roger says he has seen lots of them.

 

[petersonra]

I have seen some very old rubber cords that were connected to whole house fans in some residential attics. The cords still worked but they were dry rotted from the heat. This would not be the case in a dropped ceiling. I always wondered why it was not allowed but Roger says he has seen lots of them.

Dry rotted from the heat?

that would seem to indicate the cord was not suitable for the conditions.

 

[roger]

Have you seen rotted extension cords or rotted power cord sets?
I have seen a lot of rotted two wire rubber insulated lamp cords.
And occasional rotted round vacuum cleaner cords.

In my case I have seen more rotted cord sets than extension cords. I have replaced a good number of rotted cord sets on my power tools alone and yet have extension cords of the same age that are still in good shape.

I have seen some very old rubber cords that were connected to whole house fans in some residential attics. The cords still worked but they were dry rotted from the heat. This would not be the case in a dropped ceiling.

Why would a drop ceiling make a difference? I would say there are many drop ceilings that have never been opened since they were installed.

I always wondered why it was not allowed but Roger says he has seen lots of them.

Yes I have and if I remember correctly the panel at this years electrical institute cited this as the reason cord sets are not allowed in concealed spaces.

Dry rotted from the heat?

that would seem to indicate the cord was not suitable for the conditions.

I agree.

Roger

 

[infinity]

Dry rotted from the heat?

that would seem to indicate the cord was not suitable for the conditions.

I agree if the equipment comes with a cord suitable for the operational environment of that equipment the cord should last just as long if not longer than the equipment. I have a sump pump in my basement that 25 years old and the cord is like new even though it's been sitting in water for a good 20 years.

 

[GoldDigger]

I agree if the equipment comes with a cord suitable for the operational environment of that equipment the cord should last just as long if not longer than the equipment. I have a sump pump in my basement that 25 years old and the cord is like new even though it's been sitting in water for a good 20 years.

FWIW, a rubber cord will last a lot longer underwater than it will exposed to the oxygen in air.
And for roger, the temperatures are going to be a lot more extreme in an attic than above a dropped ceiling.

 

[infinity]

FWIW, a rubber cord will last a lot longer underwater than it will exposed to the oxygen in air.

My point was about the design of the cord, if the cord were designed for dry only use it probably wouldn't have lasted very long.

 

[Dennis Alwon]

I am sure the cords that were used 40 years ago are not the same as they are today. The cords I had seen were in the attics for a good 30-40 years ago-- dry rot but working--

 

[stephena]

Mike makes a very good point in this almost 10 minute video. The jist of the vid is that art. 400 applies to flexible cords and cables. If you go to Annex A in the back of the NEC you will see that flexible cords and cables has a product standard by UL62. Cord sets and power cords are a different standard as they are UL 817.

What does this mean? It seems that the power cords such as the cords that are part of the listing of a particular piece of equipment is allowed above a drop ceiling assuming it is not a plenum. Power cord sets are the cords such as you would find on a laptop with the power supply in the cord. Power cords are basically extension cords listed for equipment or cords that are direct wired into a piece of equipment and have a male end to get power.

He has a good point and I am curious how the cmp will address this. If art. 400 title was flexible power cords & Cables, power cords and cord sets that would solve the issue.

Any thoughts

https://www.youtube.com/watch?v=Da5SMuqQJ_8&index=15&list=PLRNS1x1jcKbHR6mAChnrfOpmm8NGop6k_

I wasn't aware that the different UL standards like 62 and 817 made article 400 rules apply to only specific investigated sections. So why would 400 only apply to UL 62? I have the UL Whitebook and I see where they specify the different UL numbers by how do you know when, why, or how to apply what to what? I really would like some help on this question. Thank you for posting this it was a great piece of information to know.

 

[Dennis Alwon]

I wasn't aware that the different UL standards like 62 and 817 made article 400 rules apply to only specific investigated sections. So why would 400 only apply to UL 62? I have the UL Whitebook and I see where they specify the different UL numbers by how do you know when, why, or how to apply what to what? I really would like some help on this question. Thank you for posting this it was a great piece of information to know.

Since the title is flexible cord and cables we look to UL who has a 67 for the product standard. So if the title is exactly as the product is listed how could it also apply to cors sets and power supply cords which has a different product standard number?