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Author Topic: Is a company switch considered a "live" tie-in?  (Read 2730 times)

Jeffery Foster

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Is a company switch considered a "live" tie-in?
« on: March 05, 2015, 12:48:10 pm »

Probably a pretty dumb question, but there you have it.  Is a fused company switch where they will be tying in bare tails considered energized?
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TJ (Tom) Cornish

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Re: Is a company switch considered a "live" tie-in?
« Reply #1 on: March 05, 2015, 02:09:22 pm »

Probably a pretty dumb question, but there you have it.  Is a fused company switch where they will be tying in bare tails considered energized?
If it's a switch, then it can be made not live.  Presumably it has a lockout mechanism to prevent it from being energized while the lugs are connected.  This does fall into "qualified operator" territory - you as a user can't make this connection.
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Jeffery Foster

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Re: Is a company switch considered a "live" tie-in?
« Reply #2 on: March 05, 2015, 03:02:03 pm »

Thank you Tom.  I wouldn't consider doing this, just want to be able to have the conversation. 
So, even though there are exposed live conductors above the fuses and switch, the fact that it is switchable and lock-out-able (yep) means it is not an energized tie in?
Thanks again!
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TJ (Tom) Cornish

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Re: Is a company switch considered a "live" tie-in?
« Reply #3 on: March 05, 2015, 03:17:57 pm »

Thank you Tom.  I wouldn't consider doing this, just want to be able to have the conversation. 
So, even though there are exposed live conductors above the fuses and switch, the fact that it is switchable and lock-out-able (yep) means it is not an energized tie in?
Thanks again!
In every definition I have ever come across, "energized" means that a device actively has power flowing through it.  Turning the switch off "de-energizes" the lugs.  Working on an energized system is very dangerous and requires flash suits and special training.  Working on a normal company switch that can be de-energized by turning the switch off is a routine task, though it still requires authorized personnel to do the work.
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TJ (Tom) Cornish

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Re: Is a company switch considered a "live" tie-in?
« Reply #4 on: March 05, 2015, 03:27:40 pm »

Thank you Tom.  I wouldn't consider doing this, just want to be able to have the conversation. 
So, even though there are exposed live conductors above the fuses and switch, the fact that it is switchable and lock-out-able (yep) means it is not an energized tie in?
Thanks again!
Reading your question again - normally the lugs are in a separate enclosure than the switch, in which case the lugs are definitely de-energizable in every sense of the word - the whole enclosure is dead.  The lockout mechanism prevents the lugs from being accidentally energized.

If the lugs are simply the load side of the fuses, it's possible that could be considered an energized situation, as you are opening a panel cover to energized equipment, even though the lugs being touched are de-energized.

What exactly is the situation you are referring to?
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Jeffery Foster

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Re: Is a company switch considered a "live" tie-in?
« Reply #5 on: March 05, 2015, 03:42:52 pm »


If the lugs are simply the load side of the fuses, it's possible that could be considered an energized situation, as you are opening a panel cover to energized equipment, even though the lugs being touched are de-energized.

What exactly is the situation you are referring to?

This is the situation I was most curious about.  I apologize if I mis-identified what would be a "company switch".
And again, I have no intention of approaching this.  These questions were just brought up after reading Richard Cadena's book.
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Steve Alves

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Re: Is a company switch considered a "live" tie-in?
« Reply #6 on: March 05, 2015, 04:10:35 pm »

That is a live energized box. It does not matter that the switch de-energizes the lower lugs. Opening the box exposes you to a live circuit.
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Steven Alves
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TJ (Tom) Cornish

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Re: Is a company switch considered a "live" tie-in?
« Reply #7 on: March 05, 2015, 04:11:58 pm »

This is the situation I was most curious about.  I apologize if I mis-identified what would be a "company switch".
And again, I have no intention of approaching this.  These questions were just brought up after reading Richard Cadena's book.
That's not really a "company switch" that's a fused disconnect.  This is a company switch:
http://www.stagecraftindustries.com/companyswitches.php

Company switches are supposed to have a separate "connection chamber" - either cam connectors, or lugs in an enclosure other than where the breaker is, so the operator isn't exposed to live terminals while making and breaking the connection.

A fused disconnect as you have described would be an energized piece of equipment, as the top of the box remains energized even with the switch off.  For low voltage situations, energized working methods aren't too onerous - OSHA defines the minimum approach distance for under 300V as "avoid contact", but you'd need gloves, insulated tools, and technically an arc flash suit, though for low voltages and small ampacities, that often doesn't happen. 

A 50A 240V disconnect on 100' of #4 wire back to the main distribution point has a lot less arc flash potential than a 200A or 400A panel on heavy wire back to the transformer.  In any case, finding an upstream breaker for your fused disconnect would be a good idea.

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Tim McCulloch

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Re: Is a company switch considered a "live" tie-in?
« Reply #8 on: March 05, 2015, 09:23:11 pm »

That is a live energized box. It does not matter that the switch de-energizes the lower lugs. Opening the box exposes you to a live circuit.

Yes, his example is a live box.

Another company switch:  http://www.lexproducts.com/products/entertainment/powergate-power-switches/200-amp-company-switches/200-amp-company-switch-type-1-indoor

For those playing along at home, note that the connection chamber has a locking door.  What you can't see is the plunger switch for the shunt trip.  If the connection door is open so is the shunt trip. :)  You can't tie in hot.  This and the 400 amp version were installed in our PAC/convention center a couple years ago.  They have a breaker box located upstage right that controls the 480v service to the transformers that feed the company switches.  We can make sure the circuit is not energized...

From a different manufacturer:  http://www.unionconnector.com/company-switch/connection-chamber-switches  Note that this unit also has shunt trip plunger switches in the CamLock recepticals.  It is not possible to energize the load side of the switch if a Cam is missing or loose, nor it is possible to energize the switch if the load chamber door is open.  These switches are installed at our arena downtown.
« Last Edit: March 06, 2015, 06:59:38 am by Tim McCulloch »
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Jeffery Foster

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Re: Is a company switch considered a "live" tie-in?
« Reply #9 on: March 05, 2015, 10:58:29 pm »

Outstanding information, gentlemen. Thanks for the clarification.
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