Extension Cords that are up to code.

[burdizzos]

There has been discussion here about what isn't up to code and some comments about what you'd need to be within code, but I'm curious. What would be required to meet the code requirements and more importantly make a safe extension cord for stage use?

 

 

I was looking at using some Carol SJOOW 12/3 and a Hubbell 4-plex receptacle with the portable box. I know it would be safe, but what would be the more correct route?

[BillESC]

You'll be fine with that gear.

[agedhorse]

Good question, and there is no definate or guaranteed answer since the code is not absolute for every situation and interpretation is left up to the authority having jurisdiction (can be the local inspector, fire department, office of the state fire marshall, OSHA, even an insurance underwriter) to say yeah or nay.

 

There are some things though, that are pretty darn clear.

 

All materials must be UL recognized (or listed) for the application. In the case of receptacles or cable or enclosures, they are recognized materials which consider such things as enclosure thickness, minimum size, clamping style/type, insulation testing, wire construction, contact tension and arrangement, ground yoke bonding and a whole bunch of other items.

 

Then there's the intended application, for example on a legitimate stage extension cables are specified to be type S or SO or SOW etc, but there is some confusion in exactly where this applies. It's pretty clear about lighting cables, but for sound, it's less clear in that most of the definitions center around theatrical lighting. Then the qurstion is further clouded when considering for example a cable that feeds the FOH position as this is not on the stage, but runs (protected) into the audience chamber.

 

The requirements are further muddied when non-"legitimate stage" applications like clubs, schools, outdoors are considered. Some local ordinances have special additional codes (seperate from the NEC) concerning portable cords and power taps (power strips, quad boxes etc) and some apply the theatrical section. One set of venues that I work falls under the office of the state fire marshall, and there's a whole different set of rules, and then I have also been allowed some leeway based on the code's allowance for some deviations where the installation is under active supervision by an accredited engineer (I am an EE, and fall under that catagory), but that has been used primarily when a combination of generator or solar power/inverter is used in conjunction with utility power. Even under supervision, we are not allowed to syncronize generators to the grid. It's for continuity in grounding and bonding of seperately derived systems (another code section).

 

So, in general if you will be working on legitimate stages (look up the definition), the suggestion is the type S (severe duty insulation) cables, and I have found that the majority of inspectors are good with SJ type cable in other applications, especially where reasonably protected. Moving down the food chain, I have also found many inspectors willing to accept the ST type cables (the thermoplastic style like the orange ones) but will pay more attention to the gauge (really should be 14 or larger) and also will become more strict as the setup looks sloppier or obvious maintenence problems exist (jacket pulled out of connector body, missing ground pins etc).

 

Now you know why the more professional companies tend to use S type cables... it eliminates some worries if an inspection occurs.

 

For power distro cables, it's ALWAYS type S, or for single conductor feeder "Entertainment Industry" approved (off the top of my head it's article 520)

 

Here's a couple of good resources:

 

http://www.chicagoartistsresource.org/?q=node/15554

 

 

interesting reading:

[burdizzos]

Good to know.

 

I'll only be using my gear on platform stages, so I probably don't have to worry too much about this sort of thing, but it's still nice to know.

[Craig Vecchione]

The Code articles that state a specific type of cable will mention "extra hard service" cable. That's the "S" if it's not followed by "J" for "junior hard service". Both designations have thermoplastic jacket variants, but you really would not want to use it as the jackets are incredibly thick and very difficult to handle.

 

If you really want to know what's okay, make a phone call to the local AHJ (authority having jurisdiction, otherwise known as the inspector or fire marshall) where you mostly plan to work, and ask. Whatever info you get is only good for their area of jurisdiction, but it will possibly buy you some goodwill with that authority...most would rather you ask now than an hour before a show in a packed club or auditorium. Just ask them what code version applies (they'll likely state a year of NEC) and whether there are any additional codes for what you're doing. If any exist they'll probably tell you to come in and get a copy of the extras, or they will have them online.