Automated Fixtures Super Crazy Electrical Issue

I had a really weird one this morning. Tour came in and wanted to hang three Mac 700s on our FOH truss. Their units use Neutrik True1 powercons, so we used the tour's fanout on our house truss soca. We used three channels of the soca to power the movers, the other three channels remained plugged into a house dimmer. Back in the dimmer room, while plugging in the mover channels to our distro, I got repeated shocks from the *male* L5-20 twist connector from the run. The channels in the house dimmer were at 0%.

Has anyone else ever been bit by the *male* connector on a power cable?

I can only think of two possibilities.

Either: There is a short somewhere in my multi that is allowing voltage to leak from one of the dimmed channels to an adjacent channel.

Or: Maybe the movers have an internal capacitor that can discharge voltage under circumstances like these?

Any insights?
 

STEVETERRY

Well-Known Member
I had a really weird one this morning. Tour came in and wanted to hang three Mac 700s on our FOH truss. Their units use Neutrik True1 powercons, so we used the tour's fanout on our house truss soca. We used three channels of the soca to power the movers, the other three channels remained plugged into a house dimmer. Back in the dimmer room, while plugging in the mover channels to our distro, I got repeated shocks from the *male* L5-20 twist connector from the run. The channels in the house dimmer were at 0%.

Has anyone else ever been bit by the *male* connector on a power cable?

I can only think of two possibilities.

Either: There is a short somewhere in my multi that is allowing voltage to leak from one of the dimmed channels to an adjacent channel.

Or: Maybe the movers have an internal capacitor that can discharge voltage under circumstances like these?

Any insights?

Can you describe how the three 120V dimmed circuits and the three 208V constant circuits entered the multicable? Was it via a male break-in? If so what where each of the 6 males plugged into and what connectors were those 6 males?

ST
 
Can you describe how the three 120V dimmed circuits and the three 208V constant circuits entered the multicable? Was it via a male break-in? If so what where each of the 6 males plugged into and what connectors were those 6 males?

ST
Constant circuits were 120v. Yes, male L5-20 break-in. 4-6 were plugged into a dimmer. 1-3 were hanging loose, waiting to be plugged to the distro. Went to straighten a pin on #1 and got bit.
 

STEVETERRY

Well-Known Member
Constant circuits were 120v. Yes, male L5-20 break-in. 4-6 were plugged into a dimmer. 1-3 were hanging loose, waiting to be plugged to the distro. Went to straighten a pin on #1 and got bit.

I would start with a careful continuity analysis of all breakouts and the trunk cable to see if there are any unexpected shorts. Any chance that any of the Socapex-type connectors had a "spun insert" which would have resulted in mis--connection?

ST
 

porkchop

Well-Known Member
I would start with a careful continuity analysis of all breakouts and the trunk cable to see if there are any unexpected shorts. Any chance that any of the Socapex-type connectors had a "spun insert" which would have resulted in mis--connection?

ST

This was my first thought. Suspect #1 would be the touring breakout. The wear and tear makes it much easier to cross plug them.
 

lwinters630

Well-Known Member
I believe it is possible thay some nutrals were shared with 208v and 120v with back feed. Just a guess as im not an expert.
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
Reminds me of the time I got a shock from touching the male pin in a Sensor Touring Rack's patchbay. Problem was a spinner, as the circuits were off by one, which is why I pulled the patch in the first place.

Other thoughts:
Neutrals are never shared in a Socapex. Grounds probably are.
The only difference between 120V and 208V wiring is each neutral is replaced by a hot from a different phase. (Discounting the non-standard Christie Lites/Strand Soco pin-out. Which, since they're using L5-20, this may very well be. Was the touring lighting supplied by Solotech or Christie, per chance?)
 
Reminds me of the time I got a shock from touching the male pin in a Sensor Touring Rack's patchbay. Problem was a spinner, as the circuits were off by one, which is why I pulled the patch in the first place.

Other thoughts:
Neutrals are never shared in a Socapex. Grounds probably are.
The only difference between 120V and 208V wiring is each neutral is replaced by a hot from a different phase. (Discounting the non-standard Christie Lites/Strand Soco pin-out. Which, since they're using L5-20, this may very well be. Was the touring lighting supplied by Solotech or Christie, per chance?)

It seems the most likely explanation is 208v configured breakout. The Mac 700 units are self-switching from 208v to 120v, and ours was the first stop on the tour where they elected to use house soca rather than run a loom. (only the third night of the tour.) It never occurred to me to question the breakout that was handed to me. Seems like a design flaw that the same soca connector is used for both configurations, allowing hazards like I experienced. Ah, well; now I know!
 

David Ashton

Well-Known Member
Crossed neutrals on the loom
 

hobbsies

Active Member
Can you describe how the three 120V dimmed circuits and the three 208V constant circuits entered the multicable? Was it via a male break-in? If so what where each of the 6 males plugged into and what connectors were those 6 males?

ST
The mac 700's can be configured for 120v or 208v. I think it's mostly swapping fuses, setting a menu command, and changing the connector but it's been a few years since I had to reconfigure one.
 

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