Disconnect Switch Arc flash protection

[Davebones]

We are having some controller cabinets built by a outside vender . They will have 480V into a breaker type switch with the handle on the cover . This is the type where you have to open the switch to open the cabinet . My question is if power still comes into the top of the switch in the controller cabinet is ARC FLASH clothing required with the door open even though the switch is open ????

 

[richxtlc]

The answer is yes as long as the feeder to the switch is energized and you are with the arc flash protection boundary. In order not to wear ppe the switch must be in an electrically safe condition, verified deenergized with the supply loto'd.

 

[RoberteFuhr]

Absolutely! NFPA 70E states that an Arc Flash exists when there are exposed energized parts or if you are interacting with equipment. See NFPA 70E for more information.

 

[jimbo123]

good information . one of my jobs is to clean out vfd's . cb is off to inside of cabinet but power is still on to line side of cb inside cabinet.

 

[dbuckley]

If you are having a panel built could you not have the breaker or disconnect in a small cabinet within the big cabinet, so that there are no exposed parts when the breaker is open. This is normal practice in Europe. Sure, it costs a bit more to build, but it means that for PM activities the only isolation you need is to open the interlocked breaker on the front panel; no PPE required.

 

[iwire]

If you are having a panel built could you not have the breaker or disconnect in a small cabinet within the big cabinet, so that there are no exposed parts when the breaker is open. This is normal practice in Europe.

I think that is the way things will go here as well. It seems the manufacturers are slow to provide us with better designed products to help us comply with 70E while not having to shut down far more then needed.

For example I work on a lot of refrigeration racks that are supplied with 480 volts, 208 volts and mixed in the same large enclosure are PLCs. So if I have to troubleshoot the 6 VDC of a PLC input I should really be shutting down the entire rack which is a problem.

If they would just separate the equipment we would be so much better off.

 

[busman]

I think that is the way things will go here as well. It seems the manufacturers are slow to provide us with better designed products to help us comply with 70E while not having to shut down far more then needed.

For example I work on a lot of refrigeration racks that are supplied with 480 volts, 208 volts and mixed in the same large enclosure are PLCs. So if I have to troubleshoot the 6 VDC of a PLC input I should really be shutting down the entire rack which is a problem.

If they would just separate the equipment we would be so much better off.

Bob,

I agree completely and would add that I sure would like to see the line side terminals of loadcenters/panelboards covered so that the local disconnect would make them safe.

Mark