Is a Lockout Required?

[Barbqranch]

I will soon be installing a new machine here at the plant. It will require both 208 V 3 phase and 120 V single phase power, and it is within 20 feet and within sight of the sub panel supplying it. Does it require a separate lockout, or can the breaker be tagged out when working on this machine?

Thanks.

 

[petersonra]

I will soon be installing a new machine here at the plant. It will require both 208 V 3 phase and 120 V single phase power, and it is within 20 feet and within sight of the sub panel supplying it. Does it require a separate lockout, or can the breaker be tagged out when working on this machine?

Thanks.

is there some reason you cannot just supply 208V 3phase plus the associated neutral to the machine?

take a look at 670.4(B) and 409.30. also 409.110(3).

 

[Smart $]

I will soon be installing a new machine here at the plant. It will require both 208 V 3 phase and 120 V single phase power, and it is within 20 feet and within sight of the sub panel supplying it. Does it require a separate lockout, or can the breaker be tagged out when working on this machine?

Thanks.

You should be good under Code. As to lockout/tagout, that'll be dependent on your documented safety procedure...

 

[Smart $]

is there some reason you cannot just supply 208V 3phase plus the associated neutral to the machine?

...

That'd be 208/120V 3? 4W...

The 120V circuit may have a different ocpd requirement... which is not integrated with the machine.

 

[Barbqranch]

That'd be 208/120V 3? 4W...

The 120V circuit may have a different ocpd requirement... which is not integrated with the machine.

Yes, this is why the separate 120 volt supply. 60 amp for the 208 3 phase, 20 amp for the 120 V (as specified by the machine manufacturer).

 

[petersonra]

That'd be 208/120V 3? 4W...

The 120V circuit may have a different ocpd requirement... which is not integrated with the machine.

it would be highly unusual (but not unheard of) to not have some kind of OCPD on the 120V circuit inside the control panel. It could certainly be added at the device if that was an issue.

 

[petersonra]

Yes, this is why the separate 120 volt supply. 60 amp for the 208 3 phase, 20 amp for the 120 V (as specified by the machine manufacturer).

UL508a generally limits control circuits to 15A. Not a hard limit though.

is that what came off the nameplate? normally the NP would show the actual FLA required plus the FLA of the largest motor as that is how you are required by code to size the circuit conductors feeding it.

 

[Barbqranch]

We don't have the machine, and hence the name plate, yet, we are in the planning stages. However, the drawing I was forwarded did state 60 amp 240 volt three phase as well as 20 amp 120 volt for the "dc power supply". Nor was there any mention of supplying 3phase 4 wire.

 

[petersonra]

We don't have the machine, and hence the name plate, yet, we are in the planning stages. However, the drawing I was forwarded did state 60 amp 240 volt three phase as well as 20 amp 120 volt for the "dc power supply". Nor was there any mention of supplying 3phase 4 wire.

your previous posts all said the 3 phase was 208, not 240.

 

[Aleman]

If you DO have 208V 3 P then getting 120 off each leg is an advantage to be used. I personally don't like for any machine to be fed by 2 separate sources. If the 60 amps will give you some extra capacity then run 4 wire and add a 20A breaker to feed your power supply. Or wire your 3 phase and get a power supply that will take 208 3 phase or 220V single. This is all kind of dumb anyway as far as I'm concerned. The machine builder should have done it right to begin with, but now you are the guy that has to deal with it. I would try to get them to make it right but if you're stuck with it then you will need to lockout both breakers to work on it. Another option is a 4 pole disconnect that can kill your 3 phase and the single. Good luck.

 

[Barbqranch]

your previous posts all said the 3 phase was 208, not 240.

Yes, that is what I said. We have 208 V three phase, the machine builder specified 240 volt 3 phase, but has assured us it will run fine on 208.