@STEVETERRY will have to answer that. But I've told the story before of renting moving lights from an AV company. They came with L6-30 connectors (so they matched their projectors) but had 18/3 whips from the manufacturer.
Voltage Drop Over Distance
- Thread starterCatwalker
- Start date
STEVETERRY
Well-Known Member
The UL listing will be based on a specific branch circuit rating and thus a specific connector rating. This situation looks simple but it is not. Consider a listed LED fixture with a dairy-chain connector built in, likely a PowerCon. The feed-through conductors also have a specific rating in the listing. If the unit was listed for use on a 20A circuit, and fed by a 30A circuit, those conductors could be subject to overloading without tripping the overcurrent protective device. Interestingly, there is nothing in NEC article 520 to prevent a 30A connector being fed by a 20A overcurrent protective device. In fact, such an arrangement is specifically allowed. So, one could change the OCPD to a lower rating that matches the rating of the fixtures being connected.
ST
BillConnerFASTC
Well-Known Member
"...with a dairy-chain connector built in..."
Wisconsin thing I guess.
So a cord on a power supply for a discharge lamp comes without a plug. Not OK to put a 30 amp plug on it and plug it into a receptacle on a 30 amp breaker?
Is it the difference of multiple receptacles that allows a common lamp with 18 gauge zip cord to be plugged into a 20 amp circuit?
Wisconsin thing I guess.
So a cord on a power supply for a discharge lamp comes without a plug. Not OK to put a 30 amp plug on it and plug it into a receptacle on a 30 amp breaker?
Is it the difference of multiple receptacles that allows a common lamp with 18 gauge zip cord to be plugged into a 20 amp circuit?
RickR
Well-Known Member
I've been told that. I've also been told that undersized cords wouldn't be allowed at all if introduced today. Same for screw lamp bases.
JD
Well-Known Member
Pretty easy to make an array of high output LEDs to produce a very powerful wash light. Another story completely in making a LED point source along the output power of a Super Trouper. I think that may be many years away. Things happen in the LED junction as you turn up the heat, and there are only so may ways to move heat away from a point source.
JD
Well-Known Member
As soon as there is a pass-through connector, then the final cable to the fixture is no longer a "whip", but a current carrying part of a larger circuit. In the case of a followspot there is no pass through. (Same with a table lamp.) I bought all of mine used, but I suspect if you bought a Super Trouper new, it would not come stock with a connector on the cable. (Could be wrong.)
techieman33
Well-Known Member
I don't know, things have improved pretty quickly. Look at fixtures like the Robe Robin DLX, or High End Solaspot pro. I would have told someone they were crazy if they told me that those were just around the corner a couple of years ago. And yeah they aren't at super trouper levels yet, but I would be very surprised if some company wasn't working on developing one right now.
STEVETERRY
Well-Known Member
teqniqal
Well-Known Member
If the wiring is to be in the neighborhood of the already hot stage lights, then the NEC (NFPA 70) requires the use of Extra Heavy Duty classified cabling. This is to prevent the cable jackets melting due to coming in contact with the hot metal of the stage lighting instruments. A read through Article 520 is always a good reminder of the special requirements of our industry.
In other words, don't use hardware store extension cables for stage lighting.
In other words, don't use hardware store extension cables for stage lighting.
theatricalmatt
Well-Known Member
And use some tie-line, too! (That picture hurts, just looking at it!)
STEVETERRY
Well-Known Member
I agree about prohibition of the use of hardware store extension cords that are not extra-hard usage. However, the extra-hard usage requirement is not just in places near hot lights. Article 520 of the NEC requires extra-hard usage cable (type S or derivatives) everywhere in a theatre or other location covered by article 520. Four exceptions to this requirement per sections 520.68 and 520.69:
1. Twofers, adapters, and breakout assemblies, which can use hard-usage cable (type SJ or derivatives) with certain tight length and/or mounting restrictions
2. High temperature supply cord assemblies that are part of a listed luminaire.
3. Supply cords of listed luminaires that do not require the high temperature assembly above, and can thus use hard-usage cords up to 1m in length.
4. Supply cords of stand lamps not over 20 amps, which can use hard-usage cord.
ST
What constitutes a "stand lamp"? Teh Googel tells me this:
but I'm pretty sure that's not what the NEC means.
STEVETERRY
Well-Known Member
From section 520.2 Definitions:
Stand Lamp (Work Light). A portable stand that contains a general-purpose luminaire or lampholder with guard for the purpose of providing general illumination on stage or in the auditorium.
In other words, a Ghost Light.
ST
Stand Lamp (Work Light). A portable stand that contains a general-purpose luminaire or lampholder with guard for the purpose of providing general illumination on stage or in the auditorium.
In other words, a Ghost Light.
ST
BillConnerFASTC
Well-Known Member
So is the UL standard for a stand light AKA ghost light any different than for the living room stand lamp pictured? Perhaps a ghost light is listed as a stage and studio fixture.
So exception three above probably doesn't cover the pictured stand lamp because the cord on that UL listed luminair is over 1 m I'd expect. Basic clip light same - usually 6' cords.
So exception three above probably doesn't cover the pictured stand lamp because the cord on that UL listed luminair is over 1 m I'd expect. Basic clip light same - usually 6' cords.
STEVETERRY
Well-Known Member
The more basic issue with the living room lamp and its ilk is the lack of hard-usage cord. 18/2 SPT zip cord doesn't qualify.
BTW, the Stand Lamp does not have a 1m limit on the length of its hard-usage cord, per 520.68(A)(2). It is a special case and different from the luminaires of 520.68(A)(3), which have a 1m limit on hard usage cord.
ST
teqniqal
Well-Known Member
Maybe this isn't the right place to ask, but does anyone know the difference between a $6 clip light from the hardware store (http://www.essentialhardware.com/power-zone-pz-300-clamp-light-8.5-202551.htm) and the $25 one (4 for $100) from Apollo Design (http://www.apollodesign.net/Products/View/4351.aspx), and the $60 one from Ace Hardware (http://www.acehardware.com/product/index.jsp?productId=1286350) !? Just curious . . .
BillConnerFASTC
Well-Known Member
The $6 one has a broken link?
JChenault
Well-Known Member
As an ex Amazonian I must post
http://www.amazon.com/dp/B000HHQ94C/?tag=controlbooth-20
It's more than 6 bucks ( 13.45). But the link seems to work.
Link to the $6 one http://www.essentialhardware.com/power-zone-pz-300-clamp-light-8.5-202551.html , it was missing an "l" at the end.
The apollo one comes with a lamp and is painted black, but I have no idea what the difference is between the ace hardware and the essential hardware one... The convenience of picking the ace one up locally?
The apollo one comes with a lamp and is painted black, but I have no idea what the difference is between the ace hardware and the essential hardware one... The convenience of picking the ace one up locally?
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