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Joined: Jan 2005
Posts: 155
Dave T Offline OP
Please go to this recently released recall notice regarding a Square D Recalls Safety Switches Due to Shock or Electrocution Hazard.

Joined: Mar 2005
Posts: 49
This information is very interesting.

One of my company's clients specifies Square D safety switches exclusively (i.e., no substitutions.) However, their spec calls for Heavy Duty. I noticed the recall are for Standard Duty. I wonder what the difference is?

Thanks for this article.

Joined: Jul 2004
Posts: 625
One wonders what you can possibly do to a knife switch to make it fail to open.

Joined: Jul 2001
Posts: 599
JBD Offline
There are major differences between Square D general/standard duty and heavy duty switches. I don't think the 30A ones have any parts in common at all. The heavy duty units are designed for 600V applications (even if they have 250V fuse spacing). The general duty units are designed for 250V max.

Joined: Oct 2004
Posts: 806
One wonders what you can possibly do to a knife switch to make it fail to open.

Just a shot it the dark..maybe the plastic "clips" that move the contact blades break, leaving the blade fully or partially closed?

Once again, just like the Xmas light recall, they don't give any details of what the bloody problem is caused by!! Very annoying.

edited to add link

[This message has been edited by mxslick (edited 12-19-2006).]

Stupid should be painful.
Joined: Mar 2004
Posts: 795
I had a landlord report that a whole apartment "shorted out" when he tried to close the knife switch. When I got there I found the insulating part of the throw lever had broken off and when he tried to close it the metal handle came into contact with the blades, that were still stuck in the slots on the line side. Made quite a boom he said. The switch was actually closed anyway, the problem was a blown fuse.

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