troffer whips

[stew]

Why is it that the manufacturers can install a whip with #16 wire connected to a 20 amp circiuit but if I have a troffer of the same type say a 4 ft 3 lamp unit I cannot use a wire size smaller than 12 for my whip?

 

[shepelec]

Manufactured assembly and UL listing.

 

[stew]

the reason I wondered is that I installe some troffers the other day that may have actually had 18 in the whip. I wondered about it but then realized that the whip is nothing more than an extension of the wire from the ballast. It the ocurred to me that hey why the heck cant i do the same thing . UL we dont neede no stinkin UL!!! It makes no sense to me at all!!!

 

[480sparky]

Manufactured assembly and UL listing.

The same reason there's 16 or 18 ga wire in the fixture itself........

 

[cadpoint]

I'm not going to defend the UL.

But if you think about for a minute, if you were to consider voltage drop for the application where would you put the smallest wire? Assuming one needed a smaller wire(IE their assembly)?

Yes there skirting the code, but then there's the Code otherwise.

 

[benaround]

stew,

The premise wiring stops at the j-box that the fixture whip ties into. The premise wiring

also stops at the wall recpt. but look at all the small gauge wire on the things we plug in.

Fixture whips are for suppling 'one' fixture, not for branch circuiting many fixtures all

together. And yes, we do need U.L.

 

[ceb58]

the reason I wondered is that I installe some troffers the other day that may have actually had 18 in the whip. I wondered about it but then realized that the whip is nothing more than an extension of the wire from the ballast. It the ocurred to me that hey why the heck cant i do the same thing . UL we dont neede no stinkin UL!!! It makes no sense to me at all!!!

I am not saying UL is perfect but can you imagine the crap that would be out there with out it.
The MFG. spend large money to design and prove there product is safe. In this case they have convinced UL that the fixture is safe with 18. Look at what the A/C mfg. do. By the NEC we size our wire and OCP per mfg name plate. Which lets us use smaller wire with larger OCP than we can any where else in the NEC. All because the A/C mfg. have install there own protection and have engineered and proven the operating conditions for there equipment.

 

[Jim W in Tampa]

That whip is just for that 1 fixture. It is plenty safe and it is not the thhn that your using. That does not mean it has not or will not be abuse by adding fixtures and we all have seen that. UL covers them.

 

[mcclary's electrical]

What about a lamp with 18 guage cord? What about a 16 guage extension cord? They all are not premise wiring. Be careful with fixture whips on layins, many local AHJ's have adopted no whip policy

 

[stew]

I fully understand what eveyone is saying I just think i does not make any good sense to have to use a # 12 whip to feed a load that is .8 amps.And neither does ul or the manufacturer that why the get approval to use thier weenie whips. But me? Nuh huh. no can do I would surely cause a fire if I used a 14 on these!! HA HA HA . It just seems to me that if the whip isnt over 6 fdt whats the big deal eh?

 

[Jim W in Tampa]

I fully understand what eveyone is saying I just think i does not make any good sense to have to use a # 12 whip to feed a load that is .8 amps.And neither does ul or the manufacturer that why the get approval to use thier weenie whips. But me? Nuh huh. no can do I would surely cause a fire if I used a 14 on these!! HA HA HA . It just seems to me that if the whip isnt over 6 fdt whats the big deal eh?

Big deal is that someone seeing your install might tap in and add more fixtures. I agree if not misused is no danger but same would apply to ceiling fan / light combo and simply is a no can do. Why is number 12 such a big deal ?

 

[btharmy]

You can buy ul listed fixture whips that are smaller than #12awg. You don't have to use #12 whips if you don't want to.

http://www.engproducts.com/OurProducts/prodSubSection.asp?SecID=4&CatID=1&SubSecID=22

 

[mcclary's electrical]

You can buy ul listed fixture whips that are smaller than #12awg. You don't have to use #12 whips if you don't want to.

http://www.engproducts.com/OurProducts/prodSubSection.asp?SecID=4&CatID=1&SubSecID=22

I agree, when I'm doing a normal size office, I'll rough in a 1900 above the ceiling grid. Then on trim out, drop in (4) 2x4 layins, 16 guage whip for each one into the box, 3 wirenuts for one office

 

[don_resqcapt19]

There is no reason why you can't make your own fixture whips using conductors with an ampacity of less than the branch circuit rating. 240.5(B)(2)(1) permits you to use up to 50' of #18 tapped off a 20 amp branch circuit, or up to 100' of #16 tapped off that same 20 amp branch circuit.

 

[LarryFine]

Look at what the A/C mfg. do. By the NEC we size our wire and OCP per mfg name plate. Which lets us use smaller wire with larger OCP than we can any where else in the NEC. All because the A/C mfg. have install there own protection and have engineered and proven the operating conditions for there equipment.

There was something in it for them: adequate handling of starting current.

Imagine being told we have to run #6 to a 30a AC because of the required breaker.

 

[LarryFine]

240.5(B)(2)(1) permits you to use up to 50' of #18 tapped off a 20 amp branch circuit, or up to 100' of #16 tapped off that same 20 amp branch circuit.

But, what's the load limit/fixture count on those conductors?

I can't wait for the flood of "Then why can't we use #14 for switched fixture legs on 20a circuits?!" responses.

 

[K2X]

I like when they daisy chain 20 or so fixtures with the #18 whips. That gets a little scary.

 

[mcclary's electrical]

I like when they daisy chain 20 or so fixtures with the #18 whips. That gets a little scary.

How do you daisy chain through a whip? unless you put two in each light

 

[Cavie]

How do you daisy chain through a whip? unless you put two in each light

You jump from fixture to fixture using the whips. The fixtures can only be 4' apart. I've seen it done but I wouldn't do it. It's much cheaper in the long run to buy whiped fixtures than non whiped and have to make up the whips. Big labor savings.

 

[mcclary's electrical]

You jump from fixture to fixture using the whips. The fixtures can only be 4' apart. I've seen it done but I wouldn't do it. It's much cheaper in the long run to buy whiped fixtures than non whiped and have to make up the whips. Big labor savings.

I didn't think anybody was stupid enough to do that. When you buy a whipped fixture, and then add another whip, you should automatically know that's not right.