The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Temporarily feeding a panel...
by Potseal
Yesterday at 11:05 PM
Locked rotor, no burnout
by jraef
Yesterday at 01:18 PM
Massive power outage South Australia
by Meadow
Yesterday at 06:46 AM
short circuit??
by Meadow
Yesterday at 06:43 AM
Norwegian power?
by Meadow
Yesterday at 06:36 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 14
sparky 10
sparky66wv 8
gfretwell 8
Potseal 7
Who's Online
0 registered (), 251 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#177816 - 05/12/08 08:52 PM welding near electronics
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
I have an installation where three DMX controlled lights failed at the same time, at about the time welding was done near one of the lights. The DMX cable is shielded and the lights are daisy-chained with separate inputs and outputs. I'm guessing the welder was the culprit.

What precautions should be taken when welding near equipment that is so sensitive that its signal cable must be shielded?

Is there a wiring method that will reduce the risk?

Top
#177825 - 05/13/08 06:43 AM Re: welding near electronics [Re: twh]
LarryC Offline
Member

Registered: 07/05/04
Posts: 775
Loc: Winchester, NH, US
You did not state what kind of welding was performed, but I will guess it was TIG. TIG uses a high voltage high frequency signal to initiate the arc. The high voltage leaks out of welding leads and that is probably what did the units in. Keep the welding leads at least 1 foot from the control cables. If the welding leads have to cross the control lines, make the crossing at right angles. Otherwise the usual items, minimize lead length, maximize distance between welding leads and suseptable cables, and if possible, have shielding (magnetic and electrostatic) between the welding leads and the victims.

Best protection would be to unplug the cables from the electronics before welding.

Larry

Top
#177831 - 05/13/08 07:30 AM Re: welding near electronics [Re: twh]
n1ist Offline
Member

Registered: 02/13/02
Posts: 176
Loc: Malden MA
Most DMX lights have the input and output connector tied in parallel. Electrically, DMX is just RS485 (5V differential) signalling.

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals