Position when pulling a disconnect - relative to cabinet

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Going through some NFPA 70 E safety training with my employer today. Good course on regulations, protective clothing, etc.
Question came up about where to stand when pulling a disconnect on a cabinet. Typically, the combination breaker handle locking disconnect is found on the right hand side of a cabinet or a large circuit breaker in a switchgear line up.
The instructor (Manuf Rep) is stating that you should suit up (wear appropriate PPE) and operate the disconnect with your right hand while standing in front of the enclosure cabinet near the hinge side of the cabinet. His theory is that cabinet door would provide additional protection in the event of a fault.
Quite a few of us have always stood on the right side of the cabinet, out of the way of the enclosure, even if on the open side (away from the hinge side), and operated the disconnect using our left hands, keeping our bodies well clear of a potential blast area. Typically in our industrial plants this is for 480 V - 2300 V starters.
What are you doing?
Any comments or recommendations?
 
Re: Position when pulling a disconnect - relative to cabinet

I think in most cases, the hazard is minimal if proper shut-down procedures are made. Open a switch under load is not a good idea. I must say I also have the habit of standing off to the side of the enclosure when opening the switch, usually with my head turned away from the enclosure.

It just seems all the important stuff is on the front of our bodies and I don't trust the door to provide any protection. If anything, it could blow of and become a projectile.
 
Re: Position when pulling a disconnect - relative to cabinet

I had an experience one time at a manufacturing facility. We heard a rather loud explosion come from one of the power distribution rooms. When it was investigated, it was found that the front door of a disconnect enclosure (4160v) had been blown completely off the enclosure. I know I would not have wanted to be standing in front of the door when it blew. The door was almost unrecognizable as it was twisted, bent, and burned.

Bob
 
Re: Position when pulling a disconnect - relative to cabinet

if the door was that managled, I wonder what would have happenned to the person standing in the doorway opening when the door channeled the arc that way.

I vote for standing behind the door. Better yet do not open under load. if forced to open under load, use a rope from the other side of the room.
 
Re: Position when pulling a disconnect - relative to cabinet

i also have a habit of standing off to the side when closing large circuit breakers when possible. i have seen one incident on a 600 amp 480 volt circuit breaker was found in the tripped position. this was g.e. switchgear --- breaker was operated by the handle in the front of the board though a mechanism. the first time the breaker was reset it tripped out. the building's chief engineer was called and he tried again to reset it ---thank goodness he was standing off to one side---the entire cover blew off the switchboard!!! sheared the hinges and stripped the three bolt arrangement and blooned out the cover!!! i was suprised at the damage. the manufacturer said it was a defective breaker and the trip unit caused the line side to flash phase to phase! i recommend standing off to the side!!! i know of one person who had two fingers broken from an fpe 200 amp breaker explosion --- back when they were having problems with defective breakers....
 
Re: Position when pulling a disconnect - relative to cabinet

These stories of horror make me think that 110.9 is being violated on a regular basis. :mad:
 
Re: Position when pulling a disconnect - relative to cabinet

By Charlie: These stories of horror make me think that 110.9 is being violated on a regular basis.
Click to expand...
Charlie you are so right. It wasn't until the past 20 years or so that I have ever heard an inspector even question a AIC rating much less a electrican know what it ment. :eek:

Even now it's very rare that I hear anyone questioning it. After an incident at a plant I was working at OSHA required us to use a 6' lond hook pole to open any switch gear that had a load on it, and we had to use the pole and PPE's to close it. There was one hanging by each disconect after that.
 
Re: Position when pulling a disconnect - relative to cabinet

I have seen these poles and hooks on a few occasions and wondered why. So the reason for them is that the plant equipment is not in compliance with the requiremetns for SC withstand capability? is that what your are saying?
 
Re: Position when pulling a disconnect - relative to cabinet

There is not a specific right answer to your question, but from the failures I have been called out to the hinges will hold, the latch will fail so the door will swing open on the hinges which may hit you possibly causing a broken arm or concussion tyoe injury. If you have ever been to a burn center you would take a broken arm over an arc flash burn any day.

However, you should also keep in mind the configuration of the equipment, other hazards that standing on one side may expose you to and available exit routes so in the event of an arc flash you are not trapped.
 
Re: Position when pulling a disconnect - relative to cabinet

I wonder why would anybody would want to reset a breaker or replace a blown fuse...without checking for, and investigating the cause and reason as to why the breaker tripped or the fuse blew, in the first place.....HMMMMMMMMM.........!!!

THAT'S WHY MEGS...ARE STILL MANUFACTURED......USE THEM...AND 99% OF THE TIMES YOU'LL FIND THE CAUSE...AND AVOID INJURY TO YOURSELVES.....!!!
 
Re: Position when pulling a disconnect - relative to cabinet

Without going into a lot of detail, because I have done this on a previous Post.
Again, I strongly recommend contacting the Bussmann representative in your area, and have a "Selective Fuse Co-ordination Program" for your site.
We upgraded our fusing at our site with Lo-Peak, Dual-Element Fusing, with the help of a Bussmann Engineer. If anyone would like to discuss this further, please contact me via the private message system. I would be glad to discuss this with anyone that is interested.
 
Re: Position when pulling a disconnect - relative to cabinet

safeguy,
I wonder why would anybody would want to reset a breaker or replace a blown fuse...without checking for, and investigating the cause and reason as to why the breaker tripped or the fuse blew, in the first place.....HMMMMMMMMM.........!!!
Click to expand...
I know that the OSHA rules require checking before resetting a breaker, but I would expect that at least 90%+ of the time the breaker is reset without any checking.
Don
 
Re: Position when pulling a disconnect - relative to cabinet

Don, The NEC and OSHA, generally speaking, do a very good job at maintaining and enforcing THE INDUSTRY GENERAL SAFETY STANDARDS across the entire spectrum...And unfortunately many of the Craftsmen...regardless of trade or profession, do a better job at not following the basic safety rules...!

I guess we all have a tendency to take things for granted.....!

I would like to see.." 90% checking before resetting or replacing....and 10% making an educated decision as to WHY NOT TO CHECK...!!!

I've seen people getting killed and others badly hurt...'cause they thought " THIS TIME IT'LL BE OK...!"
And nobody is perfect, but is just that - moment of impatience - that costs so many lives and injuries...!
I KNOW ONLY TOO WELL...! I REVIVED TWO AND THE THIRD ONE WAS TOO LATE. ANOTHER ONE LOST HIS LEFT HAND INDEX FINGER TO A 15A/120V AC BREAKER...." ...BUT IT'S ONLY 120 VOLTS...!!!" YEP.....JUST 120 VOLTS....HMMMMMMM....WELL MAYBE NEXT TIME I'LL BE FASTER THAN THE BLAST.....! YEAH...RIGHT...!!!

IS JUST ONE BREVE MOMENT....BUT YOUR LIVE WILL BE CHANGED FOR EVER....!!!
 
Re: Position when pulling a disconnect - relative to cabinet

Originally posted by safeguy:
The NEC and OSHA, generally speaking, do a very good job at maintaining and enforcing THE INDUSTRY GENERAL SAFETY STANDARDS across the entire spectrum...<snip> ANOTHER ONE LOST HIS LEFT HAND INDEX FINGER TO A 15A/120V AC BREAKER...." ...BUT IT'S ONLY 120 VOLTS...!!!" YEP.....JUST 120 VOLTS....HMMMMMMM....
Click to expand...
Where does this leave the average home owner?

They are not going to call an electrician to reset a breaker or meg the circuit before reseting.

There is nothing on the label of the panel that tells a homeowner that reseting a breaker is possibly dangerous.

By the way can you go easy on the capitols?
 
Re: Position when pulling a disconnect - relative to cabinet

TO BOB BADGER.

Hi Bob.
Thank you, for your reply. You're right in stating the question about the home owner resetting a breaker....

Well. No different than turning a lighting control switch on or off.
Yep. Things can happen...at any time!.

However, my comments and opinions are to be taken in the context used in this forum.

My writings are directed to the professional and licensed electricians and other craftsmen and repairmen.

The home owners are on a sort of a different platform with respect to safety...such as, never operate a breaker or connect an extension cord etc., with wet hands. Just to cite an example.

We all should be aware of the level of danger based on our own general and personal knowledge.

So, for us licensed electricians, craftsmen and repairmen, who are in more closed contact with the exposed switch gear, live wiring, dangerous surroundings, and making decisions which carry a heavy weight that will affect others, I think we should double check our selves...and I know the majority of us try to do that..!

Those home owners trust our knowledge and work...AND THAT'S WHY THEY DON'T HESITATE IN RESETTING A BREAKER OR OPERATE A LIGHT SWITCH....!

THEY KNOW THEY ARE SAFE....!!!

Again, is a very good observation on your part and I appreciate it.
Sorry about the CAPITALS...I'll try to improve on that...You have my word..!

Stay safe and take care.
 
at a recent seminar i attended we were told: on a right-hand disconnect stand off to the side, turn your head and shut off with your left hand. but on a center disconnect stand on the hinge side of the door.
 
I was making an inspection today, and while standing on the front porch of a house with the EC, we saw a "town" bucket truck pull up in front of the house.
Two guys got out of the truck. The younger guys went up in the bucket and started to work on the street light. We saw a large arch flash, heard the arch and watched as the young guy tried to get out of the bucket (20 ft in the air). He stood in the bucket dazed and was trying to look at his hand.
We went over to help, but he was pretty quiet, still up in the bucket. He was definitely dazed and had burned his hand. I asked him to come down and saw that his right (working hand) hand was burned. He was also blinded in both eyes from the flash, he said it felt like sand in his was in his eyes. He told me that he did not know which leg was hot and had grabbed the wrong one...barehanded.

As the two guys were just standing there I asked them a number of questions. They had:
1. no safety equipment
2. no tester in the truck
3. no training
4. they had bucket truck safety training but chose to ignore it.

They told me the town would fire them if they didn't do the work. That pissed me off.
I will not say all of what I told them, but you can imagine what I said.

The older guy went in the bucket and worked on the light... I walked away in disgust. I will call the town and tell them what I think, you can bet on it.
 
zog said:
There is not a specific right answer to your question, but from the failures I have been called out to the hinges will hold, the latch will fail so the door will swing open on the hinges which may hit you possibly causing a broken arm or concussion tyoe injury. If you have ever been to a burn center you would take a broken arm over an arc flash burn any day.

However, you should also keep in mind the configuration of the equipment, other hazards that standing on one side may expose you to and available exit routes so in the event of an arc flash you are not trapped.
Click to expand...

I can't say how things are now, but back in the 60's I was told the latches and hinges should go at the same time. Now I am not talking about the flimsy latch to prevent door opening while energized. I am referring to the door latches themselves.

I have only personally seen seven doors open or come off during a fault. On 5 of them the doors were properly latched and the whole door came off. All were badly bent and several feet or more away from the panel. In one case it was embedded in a block wall about 12' away.

I've seen mention of pulling disconnect under load. There is only 1 way I am doing that and that is in case of an extreme emergency (and I mean one where it might save a life or serious injury to someone).
 
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