Live-front vs. Dead-front

[samsrk]

What are the actual definitons of live-front and dead-front when refering to electrical equipment such as switchgear and transformers?

 

[barbeer]

Dead Front. Without live parts exposed to a person on the operating side of the equipment.

There is no definition for "live front" but why not assume the opposite of above?

 

[drbond24]

My experience is with pad mounted transformers, and the definitions are pretty much self explanatory. If you open the secondary side and you see exposed bus bars, it is a live front. If you see insulated elbow connections it is a dead front.

Overall, live front means the energized parts are readily accessible and dead front means that an attempt has been made to keep prying hands from getting their owner killed.

 

[steve66]

My experience is with pad mounted transformers, and the definitions are pretty much self explanatory. If you open the secondary side and you see exposed bus bars, it is a live front. If you see insulated elbow connections it is a dead front.

Overall, live front means the energized parts are readily accessible and dead front means that an attempt has been made to keep prying hands from getting their owner killed.

I'm not saying you're wrong, but I would have still considered the transformer with bus bars a dead front since you still have to open the secondary compartment. And that usually takes a nutdriver and a key to the padlock.

The only thing I have ever seen that would be considered livefront was bus work that were about 100 years old. It was installed in the middle and around the sides of a locked room. There was only a handrail (with a single crosspiece) to keep someone from falling into it.

Steve

 

[dbuckley]

You've spotted the key difference. It's to do with the front panel. In the Good Old Days, with knife switches, the front of switchgear was decidedly live. An operator could get shocked by being careless. Dead front means that there are no voltages present on the front panel.

Dead front became the standard yonks ago most everywhere, but theatres had live front kit for many years.

 

[jim dungar]

I'm not saying you're wrong, but I would have still considered the transformer with bus bars a dead front since you still have to open the secondary compartment. And that usually takes a nutdriver and a key to the padlock.

Your transformer was only dead front until you opened it, then it became live front.

I have never seen a true dead front LV (<=600V) pad mount connection.

In the past 18 monthe I have been involved with live front equipment at two different companies.

 

[mdshunk]

This would definately be live front:

 

[Dave_PE]

And the perfect place to have large metal object on WHEELS.

 

[drbond24]

I'm not saying you're wrong, but I would have still considered the transformer with bus bars a dead front since you still have to open the secondary compartment. And that usually takes a nutdriver and a key to the padlock.

You're not saying I'm wrong, but you disagree with me? Wouldn't that mean you were wrong?

Ok here we go. According to the library on Cooper Power's website:

Live-front
Apparatus with bus work and connections exposed to the operator.

Dead-front
Shielded to ground potential; the front plate of transformer or switchgear where al connections are insulated and totally shielded with shields visually connected to ground.

 

[steve66]

And the perfect place to have large metal object on WHEELS.

:grin: :grin:

I think Marc is going to tell us that gear isn't in use anymore. Otherwise, the shopping cart is kind of scary.

Steve

 

[steve66]

You're not saying I'm wrong, but you disagree with me? Wouldn't that mean you were wrong?

According to Jim's post, its both a dead front, and a live front. So were both right:smile:

 

[Rockyd]

We live in a fairly safe world compared to stuff from last century...I worked a short call last summer with 1/2" x 8" copper bus bars ran parallel 4 or 8 deep (didn't want to get close enough to make sure) in a refinery (lots of big DC), were just ran out in the open! They were on big stand-offs from the wall. One really wanted to pay attention to the sign on the door -

DANGER
ELECTRICAL ROOM
QUALIFIED PERSONNEL ONLY​

 

[Dave_PE]

:grin: :grin:

I think Marc is going to tell us that gear isn't in use anymore. Otherwise, the shopping cart is kind of scary.

Steve

Let's hope not...but those look like fairly new meter cans.

 

[beanland]

A Work of Art

A Work of Art

That switchgear was made by electricians who were artists. It is a work of art. And, since varnished cotton or rubber was the best insulation available, it was state-of-the-art, for its time.

 

[nakulak]

I'm guessing that the shopping cart has a sign on it that says something like "This cart to be operated by qualified personnel only !"

 

[mdshunk]

That picture of the scary switchgear is from this site in an old thread. It wasn't anything I was involved with. Read all about it:

http://forums.mikeholt.com/showthread.php?t=80798

 

[polejockey]

A live front urd transformer has the primary cables exposed,where as a dead front transformer has insulating elbows. the live front padmounts are one of the first to be introduced into the underground system but know in the past 35 years or so its been all dead fronts. thats wats the termination of live and dead fronts padmounts

 

[polejockey]

polejockey

polejockey

live front means the primary cables are exposed when opening can dead front means the primary cablles have insulating elbows plugged into a bushing