Strain relief connector 410.62 (B), (C)

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AKsparky1

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I have a 277V 1000W HPS ballast permanently fixed above a fixture. The height of the fixture is adjustable by means of jack chain. There is a 10ft cord that is connected to the ballast by a factory non-locking attachment plug and is connected to the fixture by a factory non-locking attachment plug. So a plug is on both ends of the cord. The inspector wants a special strain relief on the cord. The cost of these special strain relief connectors is about 6000 bucks as there are over 200 of these fixtures. If the code does not require it then I have to try and figure out what the inspector is trying to accomplish. The cord would simply detach at either plug under a strain. Did I miss a code rule?
 
Not quite sure what you are stating or asking, but if you argue "The cord would simply detach at either plug under a strain", then you are not in compliance with the last sentence of 410.62(B)...
The cord shall not be subject to strain or physical damage.
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AKsparky1 said:
The inspector wants a special strain relief on the cord. The cost of these special strain relief connectors is about 6000 bucks as there are over 200 of these fixtures. If the code does not require it then I have to try and figure out what the inspector is trying to accomplish....
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Finding out what the inspector is trying to accomplish is the key. I just can't see him requiring a purchase of thousands of dollars worth of strain reliefs just to satisfy his ego that he is boss. Something else is up.
 
Smart $ said:
Not quite sure what you are stating or asking, but if you argue "The cord would simply detach at either plug under a strain", then you are not in compliance with the last sentence of 410.62(B)...
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The code says that the cord shall not be subject to strain.
Obviously that is not an absolute prohibition or else no cord could ever run vertically.
If non-locking plugs are used at each end the strain will be limited to a value which is not harmful to the cord and as long as the cord ends are strain relieved to the cord there will also be no strain at all on the wires inside the cord.
I cannot argue without possibility of dispute that the code language does not prohibit this, but my opinion is that the inspector is overreaching.
Just what is this special fitting supposed to do? Attach the body of the cord to the assembly it is plugged into?
That will just result in more strain on the cord itself if something moves more than it should.
If the code said that the mated cord ends (plug and receptacle) shall not be subject to strain it would be a slightly different story.

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The typical concern is strain transmitted and potentially damaging to conductor terminations. How many times have you heard disconnect a cord by pulling the plug, not the cord? What AK posits is a contradiction to that very concept
 
Smart $ said:
The typical concern is strain transmitted and potentially damaging to conductor terminations. How many times have you heard disconnect a cord by pulling the plug, not the cord? What AK posits is a contradiction to that very concept
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A good point, but one that in part depends on the construction of the cord.
It is indisputable (which will immediately be disputed) that repeated pulling on a molded cord can damage the wires right at the cord termination.
If the cord cap has a strain relief bracket, that is not necessarily as great a problem, and nobody, as far as I can tell, is planning to repeatedly (or even once) disconnect the cord in question that way.
I would still like to know just what the fitting the inspector is asking for does and how it connects.
From the description the only strain that would ever come on the cord other than the weight of its own ten foot length will come from someone running a ladder or forklift into it or the luminaire falling.
In either of those situations, I might prefer that the cord end be pulled out of the receptacle rather than have the body of the cord rigidly fastened to the ballast or the HID fixture.
We need more information.
 
The only strain on the cord would be the weight of the 10ft cord itself which will be ty-raped to the structure. This is a factory cord and the entire unit is UL listed.
 

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AKsparky1 said:
The only strain on the cord would be the weight of the 10ft cord itself which will be ty-raped to the structure. This is a factory cord and the entire unit is UL listed.
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That looks more to me like adjustable via paracord rather than jack chain. :)

As GD mentioned, absolutely no strain is impossible in a vertical application, but as pictured avoidable strain on the cord and/or connectors will occur as the lamp fixture is lowered... if the cord remains bundled.

Also curious what strain relief means the inspector is "requesting"... :happyyes:
 
We have already decided to use jack chain instead of what was pictured. The fixture pictured was just a moc up. The strain relief the inspector wants is a kelim grip that has to be weaved around the cord and has a hook to be attached independently to a stucture. What I am saying is that no strain relief is required because there is a factory sealed attachment plug. On both ends.
410.62 (C1), 2
Is terminated in a grounding-type attachment plug cap or busway plug, or is a part of a listed assembly incorporating a manufactured wiring system connector in accordance with 604.6(C), or has a luminaire assembly with a strain relief and canopy having a maximum 152 mm (6 in.) long section of raceway for attachment to an outlet box above a suspended ceiling
 
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A Kellum (TM) grip will support the weight of the cord itself without putting any strain on the internal connections of the plug or the plug to receptacle connection.
It is required for pendant cords that support the weight of a long section plus the weight of a device box and may be accidentally pulled on.
What you have is not a pendant cord and is, as you note, an integral part of a listed assembly. It is not field wiring.
I think that argument rather than the one about the connectors limiting the strain is your best bet for making your point.

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AKsparky1 said:
We have already decided to use jack chain instead of what was pictured. The fixture pictured was just a moc up. The strain relief the inspector wants is a kelim grip that has to be weaved around the cord and has a hook to be attached independently to a stucture. What I am saying is that no strain relief is required because there is a factory sealed attachment plug. On both ends.
410.62 (C1), 2
Is terminated in a grounding-type attachment plug cap or busway plug, or is a part of a listed assembly incorporating a manufactured wiring system connector in accordance with 604.6(C), or has a luminaire assembly with a strain relief and canopy having a maximum 152 mm (6 in.) long section of raceway for attachment to an outlet box above a suspended ceiling
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Okay... but let's get something straight here before continuing. The requirements set forth by 410.62(C) are regarding the connection of the luminaire to the premises wiring outlet receptacle, not the cord interconnecting parts of the listed assembly (i.e. the cord between the driver and lamp housing).
 
Smart $ said:
Okay... but let's get something straight here before continuing. The requirements set forth by 410.62(C) are regarding the connection of the luminaire to the premises wiring outlet receptacle, not the cord interconnecting parts of the listed assembly (i.e. the cord between the driver and lamp housing).
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The scope of 410 does not say that it covers integral connections of a listed assembly. The driver or ballast, cord and lamp fixture are designed and listed for use without a kellum grip. The fixture is not a pendant and will be supported independently via jack chain. If the tenant chose to adjust the height of the fixture they can by unplugging the cord and making the adjustments with the chain links.
 
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AKsparky1 said:
The scope of 410 does not say that it covers integral connections of a listed assembly. The driver or ballast, cord and lamp fixture are designed and listed for use without a kellum grip. The fixture is not a pendant and will be supported independently via jack chain. If the tenant chose to adjust the height of the fixture they can by unplugging the cord and making the adjustments with the chain links.
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I agree with you... but what I'm telling you is listed equipment is still subject to approval by the AHJ... and if the AHJ wants to go beyond what Code or an NRTL says is safe, you have little recourse.

The inspector himself is not the AHJ. He is only a representative. He may or may not have the final say. You can try to work with him, but if he remains adamant, you just may have to go over his head, to his boss(es). However, if he does have final say, or you cannot sway the boss(es) to agree with you rather than his subordinate, you're simply going to have to suck it up and appease the man.
 
Smart $ said:
I agree with you... but what I'm telling you is listed equipment is still subject to approval by the AHJ... and if the AHJ wants to go beyond what Code or an NRTL says is safe, you have little recourse.

The inspector himself is not the AHJ. He is only a representative. He may or may not have the final say. You can try to work with him, but if he remains adamant, you just may have to go over his head, to his boss(es). However, if he does have final say, or you cannot sway the boss(es) to agree with you rather than his subordinate, you're simply going to have to suck it up and appease the man.
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So can we agree he is going above 410.62 but still subject to 90.4
 
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