The safety of outlet taps in entertainment lighting

[STEVETERRY]

Perhaps Steve Terry could clarify/confirm this, as I thought that there was an allowance in the NEC for 2-fers 18" or less in length to use the male connector as the connecting point for 2 SJ 12/3 cables.

Reason I ask as I purchased a whole lot of new 2-fers all made by TMB with splice in the male and would be surprised if they were all illegal.

SB

The whole reason the NEC allows SJO on twofers is that its smaller diameter will allow two cables into a male connector. The TMB connector (and there may be others) has an enlarged strain relief hold in the cover to accommodate two pieces of 12/3 SJO.

"V" twofers are considered by the NEC to be industry-specific safe practice when properly constructed. 36" is the max length for SJO in this application.

For more details, see this post:

http://www.controlbooth.com/forums/lighting/18270-checking-my-interpretation-nec.html#post168140

ST

 

[Soxred93]

I've seen some theatres use these: Y-splitter Liberator Power Extension - 121-2594 - SmartHomeUSA.com They're only 15 amps, but you avoid the problem of illegality and homemade problems with these things. At $4.55, you can't beat the price.

 

[STEVETERRY]

The 15amp connector debate is one we have gone around and around on. There is also a difference between a cable with a known load on the end and a cable that could have any load on the end.

NEC section 520.9 allows a branch circuit of any rating, but requires that the receptacle rating not be smaller than that of the branch circuit overcurrent protective device.

That would require a 20A receptacle on a 20A circuit. If this were an edison-plug installation, that would be a 20A t-slot receptacle. Section 520.67 allows us to plug a 15A parallel blade connector into a 20A t-slot receptacle protected by a 20A overcurrent protective device.

ST

 

[derekleffew]

I should have remembered that it's Lex Products who make the cube tap in black:

Lex Tri-Tap Adapter Cube Tap Black 50201B - Lex Products (Electrical)

NEC section 520.9 allows a branch circuit of any rating, but requires that the receptacle rating not be smaller than that of the branch circuit overcurrent protective device.

That would require a 20A receptacle on a 20A circuit. If this were an edison-plug installation, that would be a 20A t-slot receptacle. Section 520.67 allows us to plug a 15A parallel blade connector into a 20A t-slot receptacle protected by a 20A overcurrent protective device.

Still slightly unclear here. (My NFPA online reader doesn't seem to be working.) Does 520.9 refer only to permanent wiring, or encompass portable cable as well? Does receptable include cord-mounted female connectors as well as flush-mounted ones? Can the E-String only be used on 15A circuits?

PowerFLEX Cable Assemblies: E-String (3) NEMA 5-15 Receptacles Black | Lex Products

Furthering the confusion, is the 15A T-Slot female connector (with "20A. 125V" clearly stamped on its face!):

PowerPARTS Wiring Devices: Lex-Loc Edison 15 Amp Female Connector | Lex Products


Am I the only one who thinks the NEMA 5-20P

Hammond Mfg. - 15 & 20 Amp Rack Mount - With Ammeter - Outlet Strips (1583 & 1589 Series)
(and resulting debate) is tiresome? Every time I've encountered one in the field, it's been supplied with a 5-15 to 5-20 adapter; or is cut off and replaced with a 5-15P.

Does anyone know of a 20A NEMA 5-20 cube tap? Or one with a 15A male and T-Slot females? I don't think I've ever seen one.

 

[photoatdv]

Most rental companies I've encountered use edison, and will provide adapters to whatever you need (if using it with an existing system). When you ask for 2-fers or 3-fers they send out tritaps (of the black or orange variety depending)... I'm inclined to say if they feel it is safe, it probably is. The idea is anyone setting up this gear knows what they are doing. I'm also going to venture a guess that the heavy duty orange (or black) moulded tritaps would stand up to 20A without issue (not recommending, but I don't forsee any issues other than with the fire marshal). Now I kinda want to find a bad one and do some surgery...

 

[SteveB]

Am I the only one who thinks the NEMA 5-20P

(and resulting debate) is tiresome? Every time I've encountered one in the field, it's been supplied with a 5-15 to 5-20 adapter; or is cut off and replaced with a 5-15P.

Agree completely. No need for ANOTHER connector type, especially as it's the most widely used in the US and Canada. They could have kept the old 15a configuration and simply started building to 20a rating and be done with it. If you have a 15 amp circuit with over current protection at that rating - who cares ?. If you be dumb enough to load to 20 (like my sound man is doing), the breaker trips.

Right now you can have a duplex receptacle that accepts both 15 and 20 amp devices. You have no idea what the circuit rating is unless you look at the breaker. My sound guy uses cheap HD 15 amp connectors, pulls 20 on his monitor rig, the receptacle, wiring and breaker on the Sensor relay are all 20, so he fries the connector. Now I have to swap the duplex receptacle that has the single fried male prong sticking out of it.

Rant over.

SB

 

[derekleffew]

Most rental companies I've encountered use edison, ... I'm inclined to say if they feel it is safe, it probably is. The idea is anyone setting up this gear knows what they are doing. ...

Bad assumption. I know of one lighting company that uses 2P&Gs on their movers, and run them at 208V! Not illegal (as the 2P&G is rated for 125 and 250V), but a very bad practice nonetheless, in my opinion.

Yes, there have been times when I've sent 208V through an Edison, but never felt good about doing it.

 

[gafftaper]

Of these, the only one I approve of is the orange one, and someone makes them in black.

http://www.codinghorror.com/blog/2006/06/road-warrior-revisited.html

Why do you not approve of using the clear one?
Seems to me it's essentially the same thing as the orange one. All molded plastic. 3 way. Only difference I see is the shape. Do you not like the way the three plugs are lined up and jammed together so tightly?

 

[Studio]

Why do you not approve of using the clear one?
Seems to me it's essentially the same thing as the orange one. All molded plastic. 3 way. Only difference I see is the shape. Do you not like the way the three plugs are lined up and jammed together so tightly?

To me the clear tap looks to close to the white tap, and only small plugs would fit. Whereas the orange one is very different from the others and will fit large plugs.

 

[gafftaper]

The clear flat one is different from the white ones because it's molded plastic vs snapped together plastic. It's therefore more durable. You can drop it from the grid and still use it. The white ones will shatter.

I was thinking the clear flat one is actually safer than the orange because three professional size Edison plugs wont fit. This means someone can't come along and plug in three fixtures into one 15 amp tap (which is potentially pushing your luck safety wise).

 

[gafftaper]

It's completely a hijack... but yYou've got to love the socapex cube tap:

Everyone should have one just because it's just so big and cool!

 

[zuixro]

It's completely a hijack... but yYou've got to love the socapex cube tap:

Everyone should have one just because it's just so big and cool!

Anyone else see that and think "Hefty Hefty Hefty!"

 

[SteveB]

Yes, there have been times when I've sent 208V through an Edison, but never felt good about doing it.

To tie into an past thread, I'd bet Tesla wanted to send 208 through an Edison.

And I'd like to send 208 through my sound man !.

 

[JChenault]

Yes, there have been times when I've sent 208V through an Edison, but never felt good about doing it.

Derek
Just curious - why do you not feel good about sending 208 through an edison. Are you afraid that the insulation will not handle 2068 volts?

Just trying to understand if this is an emotional response, or an emotional one?

 

[Footer]

It's completely a hijack... but yYou've got to love the socapex cube tap:

Everyone should have one just because it's just so big and cool!

Those things are pretty useful, especially when dealer with par bars/six bangers. They are expensive as hell though for what they are.

 

[derekleffew]

Derek
Just curious - why do you not feel good about sending 208 through an edison. Are you afraid that the insulation will not handle 2068 volts?

Just trying to understand if this is an emotional response, or an emotional one?

No; more worried that someone will see an Edison connector and (reasonably?) assume that it carries 120V.


As to the Socapex twofer block--stupidest thing ever. Yes, let's add MORE parts, cable, connectors than necessary: that'll make troubleshooting really challenging! Gimme a regular "parbar tufer" any day.

VEAM TWOFER - UsedLighting.com

 

[gafftaper]

Yeah but you've got to admit it's the king of cube taps!

 

[derekleffew]

No, I don't; in that it meets none of the requisite characteristics of a cube tap.

 

[gafftaper]

No, I don't; in that it meets none of the requisite characteristics of a cube tap.

To quote the Church Lady "how convenient"... You wrote the definition!

(it's only because of my deep respect for the wiki that I didn't rewrite the definition and post the Lux Cube tap as part of it.)