uses permitted for flexible cord

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teco

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Had this conversation today with in-house electricians. A 200 amp bus duct switch has a cord and a threaded 2 -1/2" basket type strain relief with bushing hanging directly from the bus switch knockout. So the entire system hangs from the bus duct switch. Is this a NEC violation? Does a cord from a bus duct (busway) switch need to have attachment plugs? If not would this be an NEC violation? What do ya think?
 
Sorry if my questions are confusing. Put simply the cords hang directly from the bus duct switches with the strain reliefs. Some are hardwired directly into equipment that gets tested for a couple of months and then gets shipped out. No cord bodies. My questions refer to 368.56 and 400.7B.
Thanks.
 
sort of like this only no cord bodies and much larger ? I think you are on to something with the 400.7(b)

1100555681_2.jpg
 
teco, IMO, the cord from the busway plug-in switch needs to be supported

to the building, by approved means, within 6'-8' of the switch before it drops

to the equipment. I don't believe a cord cap and recpt. are needed in an

industrial building for connecting stationary equipment, but have no backup

to support that. Any other 'cord drop ' beside busway, would need the recpt.

and cord cap. It seems that the rules for cord drops are enforced very

differently throughout the country.
 
benaround said:
teco, IMO, the cord from the busway plug-in switch needs to be supported

to the building, by approved means, within 6'-8' of the switch before it drops

to the equipment. I don't believe a cord cap and recpt. are needed in an

industrial building for connecting stationary equipment, but have no backup

to support that....
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368.56(B) sends us to 400.7 and we need to be in accordance with those provisions...I would not argue that there are many ,many, many , instances of the misapplication of flexible cords and that many are over looked.

I guess what has to be established is ,...which one of the list of 10 ,in 400.7 is this use permitted under ,.. if it is 3 , 6, 8, 400.7 (b) applies ??
 
Looking in the 2005 handbook at 368.56 (B), Exhibit 368.2 and 368.3 it appears that the installation as I understand your description is permissible.

400.7 becomes moot (in this circumstance) since it has an exception that refers to allowing cord installation in accordance with 368.56.
 
You know,.. I looked at that section three times this morning and never saw the exception,.... now that you pointed it out ,.it seems to be the only thing on the page:roll: Thanks.
 
The exception allows a longer cord, it does not exempt you from meeting the rest of the requirements. 440.7 still applies and the cord will need to be equipped with an attachment plug. IMHO. It seems that many people want to use the "frequent interchange" excuse for using flexible cords without going to the expense of installing attachment plugs. You can't have it both ways.
 
haskindm said:
The exception allows a longer cord, it does not exempt you from meeting the rest of the requirements. 440.7 still applies and the cord will need to be equipped with an attachment plug. IMHO. It seems that many people want to use the "frequent interchange" excuse for using flexible cords without going to the expense of installing attachment plugs. You can't have it both ways.
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I agree,

400.7(B) states that where used as permitted in 400.7(A)(3), (A)(6), and (A)(8) the cord must be equipped with an attachment plug.

Chris
 
raider1 said:
I agree,

400.7(B) states that where used as permitted in 400.7(A)(3), (A)(6), and (A)(8) the cord must be equipped with an attachment plug.

Chris
Click to expand...

I'm not so sure ,..the exception follows 400.7(b) , and as it has been mentioned,.. there are graphics that show a cord directly connected to a bus duct switch and I also found this ,..
http://ecmweb.com/nec/code_quiz_052305/
For cord-and-plug connected utilization equipment, as permitted in 400.7(A)(6) and 400.7(B) of the 2005 NEC, which of the following conditions doesn't require the use of an attachment plug energized from a receptacle outlet?


A) A vertical branch circuit cable drop made from a junction box that was properly sized and supported

B) A vertical branch circuit cable drop made from a bus plug connected to a busway, meeting the requirements of 368.56(B). The attachment cap was omitted, and the equipment was wired directly

C) Cord-and-plug connected utilization equipment supplied from a receptacle outlet, in which the utilization cord cap was plugged into a wall outlet of the proper configuration and rating

D) A vertical branch circuit cable drop made from a bus plug connected to a busway. The cable was installed with two vertical and horizontal runs in this one cable installation; in other words, the cable wasn't just vertical


Answer: B)


The general rule in 400.7(B) requires cord-and-plug connected utilization equipment [400.7(A)(6)] to be supplied from a receptacle outlet through an attachment cap. An exception references 368.56, which does allow direct wiring without an attachment cap in 368.56(C).

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at necexpert@aol.com.
Click to expand...

Add it all together and it seems likely that as long as the flexible cord in the O.P. is supported properly it is not a violation.
 
While 368.56(C) is far from clear, it seems that this could be read to allow the flexible cord to be hard-wired at the supply end at the busway. It then says that the connection of equipment would need to comply with 400.7 and 400.8 which in almost all cases would require the equipment to be connected using an attachment plug. Again, if you are installing the flexible cord because you need "frequent interchange" of the equipment, then install the attachment plug so that the frequent interchange is possible. If you are going to hardwire both ends, the flexible cord shouldn't be installed at all.
 
haskindm said:
.......If you are going to hardwire both ends, the flexible cord shouldn't be installed at all.
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I've always heard this (plus read it in the NEC) and always wondered why? What is so bad about using flexible cords and cables as a wiring method? Just curious.
 
My guess is that if it hardwired on both ends it is "a substitute for the fixed wiring of the structure" which is a violation of 400.8. The code allows flexible cords to be installed where needed, but if not needed other wiring methods are more appropriate and should be used. I once followed another electrician on a job who had literally cut the ends off his extension cord and pulled it into EMT conduit rather than install the proper conductors.
 
This is from a Mike Holt article for EC&M

[FONT=Arial, Helvetica, sans-serif]
[FONT=Arial, Helvetica, sans-serif]The concept of not using flexible cords in place of Chapter 3 wiring methods sets the tone for [400.7] and [4008]. Consider the example of an appliance factory that violated this concept. Severe power quality problems in the finishing area resulted in unscheduled shutdowns and high scrap rates at a cost of nearly a million dollars per month.[/FONT]
[FONT=Arial, Helvetica, sans-serif]An associate of mine investigated these problems, and was amazed to see a 2-foot thick bundle of flexible cords (SO wire) held together by hundreds of tie-wraps. This bundle ran from several 480V breakers to loads over 200 feet away. Those loads included 10HP motors and 120/208V transformers![/FONT]
[FONT=Arial, Helvetica, sans-serif]Redoing this installation to conform to Article 400 and Chapter 3 eliminated the power quality problems-and a major fire hazard. The payback period was just a few days, based on the power quality issues alone. While this is an extreme example, it illustrates the concept of using flexible cords for what they are intended to do and using Chapter 3 wiring methods where required.[/FONT]
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That would be one reason[/FONT]​
 
Great quote!
Many flexible cords are installed out of laziness IMHO. I used to work at a government installation and found SO cord running everywhere. What a mess.
 
M. D. said:
[FONT=Arial, Helvetica, sans-serif]


That would be one reason​
[/FONT]
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While I do not diagree with the code violations, I believe the cause of the problems was not with the cords, but with the quality of the installation.

I bet the installer did not know of the special termination requirements of a lot of cords. Most breakers and lugs are not listed to accept fine stranded wire. The quality problems may have been that the cords were undersized for the voltage drop requirements and the terminations were improperly made. The bundling of the cords is also problem.
 
In my experience flexible cords are just not as durable as permanent wiring methods. I once had to make some repairs inside a radar dome that had been wired with SO Cord. After about 10-years the cord was rotten and the insulation was just flaking off leaving bare copper conductors. The interior of the dome was climate controlled, no direct sunlight, and no other deteriorating agents that I could identify. The electrical loads were very light. The cord just did not do well as a permanent wiring method.
 
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