Safety Switch or Disconnect Switch

[Alwayslearningelec]

What is the correct term for this type of switch. Is there one in the NEC for it?

 

[jim dungar]

Both terms are correct and interchangeable.
The term "safety switch" refers to an enclosed switch and goes back some 100+ years when open style, think Dr. Frankenstein, switches were very common. In fact putting enclosures around open style switches is responsible for the name 'Square D'

Of course there will be some local slang usage that comes into play, just like there is for many electrical products.

 

[electrofelon]

Safety switch or fused disconnect. There is not a separate NEC article for these, just article 404.

 

[garbo]

Have to say fused or non fused safety switch when asking for one at supply houses. One time I asked for a 250 volt three pole non fused safety switch and after I took it up to the roof & opened the box found out it had two poles and a neutral block. Never made that mistake again. Wish they still made the original best in class bullet proof Bulldog safety switches like the ones they made in the 1970's. They got sold at least twice and turned into garbage with plastic parts inside.

 

[Jraef]

Of course there will be some local slang usage that comes into play, just like there is for many electrical products.

Personally, I dislike the use of the term “disco” for this. I lived through the Disco era, I don’t ever want to be reminded of that…

 

[PaulMmn]

Personally, I dislike the use of the term “disco” for this. I lived through the Disco era, I don’t ever want to be reminded of that…

Still have your Leisure Suits, huh??

 

[OldBroadcastTech]

Still have your Leisure Suits, huh??

No, but I have the 'Extended Disco Version' of andy Kim's "Rock Me Gently"

It was produced by some Philadelphia disc jockeys

 

[infinity]

I see no reason to use the term safety switch. Disconnect switch is much more useful.

 

[LarryFine]

In fact putting enclosures around open style switches is responsible for the name 'Square D'

 

[synchro]

Personally, I dislike the use of the term “disco” for this. I lived through the Disco era, I don’t ever want to be reminded of that…

Two of my coworkers were at the Disco Demolition Night at Comiskey Park in Chicago, but they stayed in there seats and were not part of the crowd that rushed the field. At least that's what they told us.

https://en.wikipedia.org/wiki/Disco_Demolition_Night

 

[Jraef]

Still have your Leisure Suits, huh??

Nooooo!
My girlfriend at that time was a huge fan of Donna Sumner and i got my fill of that genre… for a lifetime.

 

[jaggedben]

Two of my coworkers were at the Disco Demolition Night at Comiskey Park in Chicago, but they stayed in there seats and were not part of the crowd that rushed the field. At least that's what they told us.

https://en.wikipedia.org/wiki/Disco_Demolition_Night

I did not know about this. Thank you.

 

[ggunn]

Still have your Leisure Suits, huh??

Actually, I do. Once a year I go to a party during Mardi Gras in Lafayette, LA, where leisure suits are the costume of choice for the male participants. The women dress as Krewe Sluts. That's a Frank Zappa reference for those of you too young to remember Uncle Frank

 

[Jraef]

I see no reason to use the term safety switch. Disconnect switch is much more useful.

A “disconnect switch” can be any number of devices, a safety switch (in this context) is a specific type of disconnect switch.

The Square D story, for those who never heard it, is that the company was originally called McBride Manufacturing Co., but started making fuses, so changed to the "Detroit Fuse Manufacturing Co." based, obviously, in Detroit. But at the time, fused switches were, as mentioned, the open knife switches, like in the Frankenstein movie set, where anyone walking by and brushing up against the conductive parts could be shocked or killed. Ford wanted something less dangerous for their new assembly lines and since they were using Detroit fuses, Ford came to them for ideas. Detroit Fuse enclosed the knife switch (at first in a cast iron box, but by 1915 it became sheet metal) with a handle to the outside to operate it.


The idea was wildly popular. Detroit Fuse put their logo on the front of the box, a "D" for Detroit, in a square box, to represent the enclosed aspect of it. But over time, people just kept referring to them as "them switches with the square and D on 'em". Eventually that became so much more important to their business than the fuses, that they sold off the fuse production and changed the name of the company to The Square D Co. (and later, just Square D).

1921 advertisement;