downsizing wire size to a light fixture

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Jerramundi said:
Personally, I don't think ANY component in a circuit should EVER dip below that of the OCPD rating, not even internal fixture wiring... unless, for example, after crossing a ballast/driver with a built in OCPD that protects the smaller, secondary conductors...

...but I'm not an engineer. I know a lot about the physics of electricity, code requirements, installation methods, et. all, but I'm not yet a "Master Electrician." I give myself the rating of a Sophomore Journeyman as I just recently crossed the 10 year mark, although I haven't yet taken any sort of Journeyman exam. I'm also FAR from graduating from MIT w/ a Masters in Electrical Engineering, lol. I have some humility, lol.
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Even the cord on an electric can opener, a lamp, coffee maker?
 
jusme123 said:
Even the cord on an electric can opener, a lamp, coffee maker?
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I really don't wanna re-hash this... but part of me thinks yes. Some coffee markers and can openers are gonna pull 15A - 20A anyway. Would it be so crazy to manufacture these items with 15A - 20A cords? A single lamp is a bit more extreme of an example and more in line with what this thread was/is about... but part of me still thinks yes for the simple fact that if current pulled on the entirety of the circuit could NEVER, and I mean NEVER, exceed the conductor ampacity rating because of the OCPD rating, it would arguably be a tad bit safer. I look at the cable connecting those appliances as part of the branch circuit like any other conductor.
 
It must just kill you when you wire a 200 amp residential service with 2/0 or 3/0 Cu and the utility provides a #2 Al service drop!
 
nizak said:
It must just kill you when you wire a 200 amp residential service with 2/0 or 3/0 Cu and the utility provides a #2 Al service drop!
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Kill? No. Bug? Yes.. As it should. It's inconsistent governance. Plain and simple.
Either one is factually sufficient, or the other one is. Can't have it both ways.

I guess some of us are just more apathetic than others. Me, I notice these things and have a thirst for logical answers.
Just punching in, punching out and taking home a paycheck isn't enough for me.
 
CodeQuandary said:
I realize now that I'm quite ignorant of the proper application of 402 Fixture wires.
I thought they were wires inside listed devices, I guess. Or maybe flexible plug-in cords.
I can't think of having seen these on jobs: I think they would have stood out as too-small conductors...
For example, 402 points back to 240.5 which describes required OCPDs for fixture wires, and 240.5(B)(2) says you can have 50' of 18 AWG on a 20A breaker!!!!! 100' of 16 AWG on a 20A breaker!
I'm sort of dumbfounded that I'd never noticed this before. 402 mentions having it installed in conduit, so this is not about plug-in cords or flexibility.
I wonder how often people see this used, and in what kinds of circumstances.
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You never installed fixture whips with 16 or 18 AWG conductors on troffer lights? They are taking advantage of the rules mentioned in those applications.
 
nizak said:
It must just kill you when you wire a 200 amp residential service with 2/0 or 3/0 Cu and the utility provides a #2 Al service drop!
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I kind of could care less if they run #2 Al drop, unless it is going to cause significant voltage drop. Otherwise it is part of their system and they can do what they want. Sort of no different than having a 200 amp service and they only supply it with a 25 KVA transformer, seen some even on a 15. But if you do have the load they will not deliver the voltage so well.
 
Some thoughts:

1) Watch out for assuming a binary (safe vs not safe) when the reality is a gradation of safety. 18 ga wire on a 20A circuit may be 'safe enough' in one circumstance (loaded by a lamp or a clock, visible cord that can be replaced when there is obvious damage) but not 'safe enough' in other circumstances.

2) Code is not handed down from on high, but is a creation of humans tying to provide practical safeguarding, not perfection.

3) I'd also much prefer if all small gauge cords had fuses in the cord cap to protect the cord conductors.

4) Some of us have CDO, a condition that is very similar to OCD, but the letters are in proper alphabetical order dammit. (Tongue firmly in cheek.)

-Jon
 
winnie said:
1) Watch out for assuming a binary (safe vs not safe) when the reality is a gradation of safety.
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Excellent point about dichotomous absolutes in logic.
winnie said:
3) I'd also much prefer if all small gauge cords had fuses in the cord cap to protect the cord conductors.
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Yup.
winnie said:
4) Some of us have CDO, a condition that is very similar to OCD, but the letters are in proper alphabetical order dammit. (Tongue firmly in cheek.)
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Nice, lol.
 
kwired said:
I kind of could care less if they run #2 Al drop, unless it is going to cause significant voltage drop. Otherwise it is part of their system and they can do what they want. Sort of no different than having a 200 amp service and they only supply it with a 25 KVA transformer, seen some even on a 15. But if you do have the load they will not deliver the voltage so well.
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Fair enough. It is, as you put it, "their system" and subsequently their responsibility. I'm not about to go protesting Com Ed until they make all 200 Amp Service Drops 3/0 cu, lol. But from an academic stand point, yea, it does bug me a little bit that it's inconsistent with our rules.

I guess you could say that I both care and don't care at the same time. I care academically that there exists a conflict because if it is sufficient for the POCO, it should be sufficient for the EC. Physics doesn't care.
 
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