Is this energized work ?

[bure961]

I came incontact with ss panel box that contaned a 480v disconnect to shut power off in panel .This panel has7 fuse holders inside one for each load @277v. Can qualified worker open panel wearing ppe to pull fuse while panel is still energised ? Would this be covered under testing, troubleshooting , or loto ? Should this haveto be shut down or treated as energized work? Thank you for any response to the questions. Fuses are 5 amp.

 

[petersonra]

It is likely energized work.

Whether it is something you can do while the thing is energized is a different question. It depends at least in part on why you are doing whatever it is you are doing.

Since they are such small fuses, chances are there is not much risk of a substantial arc flash, but it should be marked with how much incident energy is available.

I am not a huge fan of the rules that are found in NFPA70E about energized work, especially for situations where there is very little chance of an arc flash. But they are the rules if you follow that code.

The problem is that even with little in the way of danger from an arc flash there is still some chance of electrocution. Sometimes that can be reduced to something acceptable by various ways.

OTOH, sometimes you get equipment that the way it is designed it is just asking for trouble to work on it energized.

These days it is relatively safe to work in a lot of stuff as there are often covers in place that make it very hard to unintentionally touch anything that is hot.

 

[Jraef]

I came incontact with ss panel box that contaned a 480v disconnect to shut power off in panel .This panel has7 fuse holders inside one for each load @277v. Can qualified worker open panel wearing ppe to pull fuse while panel is still energised ? Would this be covered under testing, troubleshooting , or loto ? Should this haveto be shut down or treated as energized work? Thank you for any response to the questions. Fuses are 5 amp.

Aside from Bob's answer, I'm not sure if you meant can someone replace one fuse in the fused disconnect while leaving the disconnect switch energized, meaning not turning it off. If that's what you meant, then this is NOT someting that should be done! Pulling the wrong fuse, i.e. one still under load with current flowing, is very dangerous and is not allowed. The switch must be in the off position.

 

[bure961]

I should have explained a little better . The fuse is feeding a relay and before the fuse is pulled the control power opens a relay that has the 277 passing through to the load. I can not confirm as per 70e without going into panel and pulling that fuse and then test . there is no load on fuse when pulling out.

 

[petersonra]

I should have explained a little better . The fuse is feeding a relay and before the fuse is pulled the control power opens a relay that has the 277 passing through to the load. I can not confirm as per 70e without going into panel and pulling that fuse and then test . there is no load on fuse when pulling out.

are you trying to use the relay as a LOTO method?

 

[PowerSupportElec]

are you trying to use the relay as a LOTO method?

Just shove your screwdriver in it so it can't close, then put a tag on the screwdriver.

 

[hurk27]

I do not agree with the determination that there is little chance of an arc flash from happening because the fuses are only 5 amps, since you are exposed to the line side of these fuses and they could very easily flash over on the line side the arc flash calculations would have to be done from this side of the fuse, if these fuses are on different phases then you have the energy that is available from 480 volts, without seeing this installation it would be hard to make any determination of the safety, I would say be safe and turn off the power and LOTOTO, we watched a video of a person who was just testing a 480 volt 30 amp disconnect and while holding the leads to his meter he also has his screw driver that he used to turn the safety release so he could open the door of the disconnect in his hand, the screw driver made contact from the bar that pulls out the contacts and the middle phase on the line side of the fuse, it blew and burned him really bad right in the face, and the disconnect only had 10 amp fuses in it, but the disconnect was only 5 feet from the 2k amp MDP that fed it and was fed with 10 awg conductors, so there was a lot of incident energy available.

 

[petersonra]

I do not agree with the determination that there is little chance of an arc flash from happening because the fuses are only 5 amps, since you are exposed to the line side of these fuses and they could very easily flash over on the line side the arc flash calculations would have to be done from this side of the fuse, if these fuses are on different phases then you have the energy that is available from 480 volts, without seeing this installation it would be hard to make any determination of the safety, I would say be safe and turn off the power and LOTOTO, we watched a video of a person who was just testing a 480 volt 30 amp disconnect and while holding the leads to his meter he also has his screw driver that he used to turn the safety release so he could open the door of the disconnect in his hand, the screw driver made contact from the bar that pulls out the contacts and the middle phase on the line side of the fuse, it blew and burned him really bad right in the face, and the disconnect only had 10 amp fuses in it, but the disconnect was only 5 feet from the 2k amp MDP that fed it and was fed with 10 awg conductors, so there was a lot of incident energy available.

I agree that without someone running the numbers you can't tell for sure, but given the smallish fuses unless there is something unusual about this application chances are the IE is relatively low. You can always come up with an oddball situation that is not the norm.

 

[bure961]

Thank you all for your time and responses, all use full information.

 

[jumper]

bure,

Are you the person being asked to change these fuses?

 

[bure961]

jumper, no I was trying to get it across to some people they could not enter the panel box without ppe and being trained . The questions I asked were the questions they asked me about doing the work. They think I was being a pita by telling them the little I knew about this being complient in getting the job done. It is something they always did before and don,t think things should change. I was looking for reasurance that this wasn,t being done right. Thanks for the help.

 

[petersonra]

jumper, no I was trying to get it across to some people they could not enter the panel box without ppe and being trained . The questions I asked were the questions they asked me about doing the work. They think I was being a pita by telling them the little I knew about this being complient in getting the job done. It is something they always did before and don,t think things should change. I was looking for reasurance that this wasn,t being done right. Thanks for the help.

there is training required regardless of the PPE issue. You can't just send some guy in off the street to do electrical work.