Film-Tech Forum ARCHIVE: Lamphouse Wiring

This is topic Lamphouse Wiring in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Barry Floyd (Member # 385) on 08-18-2003, 09:57 AM:

I've got to go pick up the wire today that will run from the rectifier to the lamphouse. My "tech" told me to get "DC cables". What an I susposed to get?

My rectifier is a Kniesly "Kni-tron" (4kw), and my lamphouse is a 4kw Xenex II.

I've looked in both manuals, but neither specify what type or size of wire. The electrical contractor is NOT hooking up the projection equipment, the tech is.

Any help would be appreciated.

Posted by Gordon McLeod (Member # 33) on 08-18-2003, 10:15 AM:

You can use welding cable probably #1 but specifie that it needs to have an insulation rating of 600volts to be UL approvable (it is often reffered to as "Entertainment Cable" now
It is for use in free air only so a fiberglass sleeve (alpha makes those) should be put over it
The other type is a fiberglass braided teflon cable

Posted by Barry Floyd (Member # 385) on 08-18-2003, 10:20 AM:

quote:
It is for use in free air only so a fiberglass sleeve (alpha makes those) should be put over it

Are you saying that it shouldn't be in a "liquid-tight" conduit running from the rectifier to the lamp?

The manuals also mention a "GREENFIELD fitting"... what the heck is that?

Posted by Ken Layton (Member # 133) on 08-18-2003, 10:28 AM:

Greenfield is another term for flex conduit.

Posted by Peter Hall (Member # 695) on 08-18-2003, 11:10 AM:

It's DC so we'd reccomend stranded cable rather than solid - it's more suitable for high I DC and keeps inductance to a minimum.. Reccomemd minimum of 16mm diameter..

Posted by Steve Guttag (Member # 268) on 08-18-2003, 12:08 PM:

For 4KW lamps, #2 awg should suffice. As Gord said, use "welding" cable. It has a high-strand count and is suitable for DC. It is also often available in Black and Red (or orange).

As to the covering...I always use Greenfield (metallic flexible) or "sealtite" for the rectifier to lamphouse run.

Steve

Posted by Will Kutler (Member # 770) on 08-18-2003, 12:16 PM:

Gord and Steve are correct. But keep this rule in mind: it never hurts to use a larger guage cable/wire...or one that is larger than necessary. But by anymeans, do not use an underrated cable. This rule can apply to any type of electrical circuit.

Posted by Barry Floyd (Member # 385) on 08-18-2003, 01:17 PM:

I checked with the electrical parts house in Nashville, and they don't carry anything that big. They could order it, but it would take 7-10 days.

I called Kniesley direct, and spoke with someone there. They had the cable in-stock, and said it would be #4 SMRL. I ordered it directly from them, and they will custom manufacture it to the length I require, complete with the cable ends ready to hook up. I thought the price would end up being outrageous, but it wasn't really that bad.

Thanks everyone for your help.

Posted by Tim Reed (Member # 137) on 08-18-2003, 05:15 PM:

A welding supply house would've had it.

Posted by Paul G. Thompson (Member # 655) on 08-18-2003, 10:54 PM:

And if you ordered that cable from Kneisley, make sure you get a UL Certification and specifications with it. Without it, the electrical inspector could refuse to "sign you off" until the documents are produced.

Posted by Rick Long (Member # 213) on 08-18-2003, 11:20 PM:

Post deleted due to placement in worng topic.

[ 08-19-2003, 07:50 PM: Message edited by: Rick Long ]

Posted by William H. Ward (Member # 1797) on 08-20-2003, 10:34 AM:

Ever hear of "motion picture cable"? It was very fine stranded copper wire with, above all things, asbestos insulation. It is very flexible and came in sizes of #6 to 4-Ought. I am sure they have done away with the asbestos and most likley went to a safer cover. I worked with that type of cable for many years and never had any kind of problem.

Posted by Gordon McLeod (Member # 33) on 08-20-2003, 12:49 PM:

Asbestoes covered cable is illegal in canada and most theatre insurance forms have a clause requireing its removal

Posted by William Hooper (Member # 71) on 08-22-2003, 01:03 AM: