LOTO question

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petersonra

petersonra

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Northern illinois
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engineer
A customer has asked us to provide some means of locking out the electrical supply to a piece of equipment we are providing them.

Power is supplied to the unit via camlok connectors and a 120V male receptacle.

There is nothing real obvious that I can think of to LO this type of equipment so what I have been considering is putting these devices inside a piece of hinged wire way. The lid would have to be open to plug in the cables and once the cables were removed, the door could be closed and locked with a padlock.

Its occurred to me that one could not actually see inside the wire way that the connection was open. Is that a requirement?

The other thing I have considered is some kind of transparent cover but I'd probably have to make something and it might not be all that attractive.
 
petersonra

petersonra

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Location
Northern illinois
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engineer
Dennis Alwon said:
What about adding a disconnect switch that can have a lock on it?
Click to expand...

It would need to be a 6 pole switch, at something like 400A. Not sure if there is such a thing.

ron said:
Would something like this work?
http://www.bradyid.com/bradyid/pdv/...evices/Brady-Plug-Lockout-Large/Overview.html
Click to expand...
Not really. The thing does not have a power cord. It has a male receptacle, and is powered by a female mating plug on a cord hanging from the ceiling. I know this is a bit wierd, but they have hundreds, maybe thousands of pieces of equipment set up like this.
 
I

IMM_Doctor

Senior Member
How many sources?

How many sources?

petersonra said:
It would need to be a 6 pole switch, at something like 400A. Not sure if there is such a thing.


Not really. The thing does not have a power cord. It has a male receptacle, and is powered by a female mating plug on a cord hanging from the ceiling. I know this is a bit wierd, but they have hundreds, maybe thousands of pieces of equipment set up like this.
Click to expand...

6-pole? It sounds as if there are multiple sources.
Is there a 400 amp 3-phase source, AND a 120 volt single phase male flanged inlet?
 
ron

ron

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Location
New York, 40.7514,-73.9925
A male receptacle? So that if you touch the male end of the receptacle, you get shocked? Is here some type of inlet flange to protect your fingers? If not, that is a code violation.
 
petersonra

petersonra

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Location
Northern illinois
Occupation
engineer
ron said:
A male receptacle? So that if you touch the male end of the receptacle, you get shocked? Is here some type of inlet flange to protect your fingers? If not, that is a code violation.
Click to expand...

The (twistlock) male receptacle is on the equipment. The female plug is on a cord that comes down from the ceiling with 120V power.

When the cord is disconnected there is no power on the male receptacle.
 
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petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
IMM_Doctor said:
6-pole? It sounds as if there are multiple sources.
Is there a 400 amp 3-phase source, AND a 120 volt single phase male flanged inlet?
Click to expand...
yes to both.

there are 3 hots and 3 neutrals, plus the 120V control power. the three hots and 3 neutrals can be configured as either three separate single phase sources, or one 3 phase wye source.

these receptacles are mounted on the top of the equipment and are fed from the cable trays above.
 
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I

IMM_Doctor

Senior Member
Are you looking to retrofit existing equipment, or just move forward with new installations?

If you do not require to open the grounded (neutral) conductors, then at minimum you would need a 4-pole lockable discoonnect means, to open the (3) 400 amp ungrounded conductors, and the (1) 120v ungrounded conductor.

I Googled 4-Pole 400a disconnect and got many hits including:
http://www.bussmann.com/library/docs/Disconnect/EnclosedFusibleDisconnectSwitches.pdf
 
rbalex

rbalex

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Professional Electrical Engineer
Bob,

I’ve looked at your proposed solution in the OP and several of your responses. Basically it appears sound – with a few caveats.

Your OP hit on one significant problem:
“Its occurred to me that one could not actually see inside the wire way that the connection was open. Is that a requirement?”
Click to expand...
In fact, it is a basic requirement, but not necessarily from the equipment’s point of view.[NFPA 70E, Sec 120.2(F)(2)(c)] The actual “specs” on the lockout device itself are surprisingly few. [Sect 120.2(E)(3)].

The gut-buster is the required procedures. [Sec 120.2(F)] Especially when you realize the whole process must be documented [Sec 120.1(4)] and audited. [Sec 120.2(3)(C)] However, those were requirements in the first place.
 
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petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
rbalex said:
Bob,

I?ve looked at your proposed solution in the OP and several of your responses. Basically it appears sound ? with a few caveats.

Your OP hit on one significant problem: In fact, it is a basic requirement, but not necessarily from the equipment?s point of view.[NFPA 70E, Sec 120.2(F)(2)(c)] The actual ?specs? on the lockout device itself are surprisingly few. [Sect 120.2(E)(3)].

The gut-buster is the required procedures. [Sec 120.2(F)] Especially when you realize the whole process must be documented [Sec 120.1(4)] and audited. [Sec 120.2(3)(C)] However, those were requirements in the first place.
Click to expand...

I don't have to worry about creating the LOTO procedure. The end user has people who do that for a living. I just have to give them some means to accomplish it.

I am thinking a lockable box with a window in it would suffice. Or perhaps some kind of transparent cover. Hoffman makes several boxes that seem appropriate.
 
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