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#124491 - 10/10/06 10:38 PM Punished Bus Bars  
Admin  Offline

Joined: Oct 2000
Posts: 3,439
Not a good idea...

If you have a switch opening and you think it is a nuisance, this is not the way to deal with it. Got these pictures from a Service Tech from a generator company after they were called in to supply power to this Washington DC hotel. Over-riding a switch is a bad idea.

[Linked Image]

[Linked Image]

[Linked Image]

[Linked Image]

Tools for Electricians:

#124492 - 10/10/06 10:51 PM Re: Punished Bus Bars  
mahlere  Offline
Joined: Nov 2005
Posts: 507
New Jersey
i don't know, if I am the company that gets called in to replace it, i think it's a good idea that someone overrode the switch [Linked Image]

#124493 - 10/11/06 03:41 PM Re: Punished Bus Bars  
gideonr  Offline
Joined: Dec 2004
Posts: 161
Edinburgh, Scotland, UK
Suggests a design fault: no switch should be jammable in the on position.

#124494 - 10/12/06 02:12 PM Re: Punished Bus Bars  
napervillesoundtech  Offline
Joined: Feb 2006
Posts: 144
Naperville, IL, USA
I've never dealt with anything like that before, but, I do know that SquareD QO CB's will trip regardless of what you do to the handle. You just won't be able to reset them after a stunt like this.

#124495 - 10/12/06 02:18 PM Re: Punished Bus Bars  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
That looks like a fused switch so holding the handle closed should not effect the fuses ability to open.

Perhaps the gear was overheating and the switch itself was losing contact so some idiot decided to tie it firm.

Bob Badger
Construction & Maintenance Electrician

#124496 - 10/13/06 02:34 AM Re: Punished Bus Bars  
e57  Offline
Joined: May 2003
Posts: 2,876
Oh I've heard about this, it's one of those experiments where you try to turn copper into gold via transition metal oxidation.... Just heat it to near its melting point and scorch in a few more electrons and presto!

Anyway, from all appearances the fault was before the switch that finally it this gear in. (Between the CT cab and switch gear?) I imagine that the fuses, might not be right, they just might be a few sticks of copper pipe? Then the busswork sagged for the final blow.

Correct me if Im wrong, doesn't this type of switch have an interlock for the door, and kind of a snap action spring loaded mechanism on the knife contacts inside? I'm speculating here that someone tried to open the switch but it was welded shut - maybe it has no OCP at all... And that cord was attempt to close the door, not to have molten metal splash around the room? I imagine that switch has some charcoal as the insulated potion of the mechanism as self destructed in operation.

Mark Heller
"Well - I oughta....." -Jackie Gleason

#124497 - 10/14/06 02:57 AM Re: Punished Bus Bars  
RODALCO  Offline
Joined: Dec 2005
Posts: 854
Titirangi, Akld, New Zealand
Brainless fools who do that. [Linked Image]

Technically the fuses within the switch should still operate unless someone replaced them with solid bars or so.

I take it that those busbars are before that switch, but it looks that the lower one has been very very hot and created a flash to the steel cabinet, a very large current must have past through those bars to discolour the copper like that.

The product of rotation, excitation and flux produces electricty.

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