Fusible Panelboard

[necnotevenclose]

Does anyone happen to know if there is a 100% fusible panelboard available? I know that Bussman makes one but it is MLO. I also saw that Littlefuse came out with something similar but the site says that it has a MCB so I'm not sure how one could selectively coordinate that if it is not a main fuse?

 

[jim dungar]

Does anyone happen to know if there is a 100% fusible panelboard available? I know that Bussman makes one but it is MLO. I also saw that Littlefuse came out with something similar but the site says that it has a MCB so I'm not sure how one could selectively coordinate that if it is not a main fuse?

I am curious, why do you need a 100% fusible panelboard especially one with a fusible main?

 

[mdshunk]

Can you still get those "breakers" that you put in a QO panel that has a little flip out door to put a fuse inside?

 

[electricalperson]

Can you still get those "breakers" that you put in a QO panel that has a little flip out door to put a fuse inside?

do you have a picture of one of those?

 

[mdshunk]

do you have a picture of one of those?

I can take some. I've got some new, on the shelf in boxes, but not here at home. They looked like a regular QO breaker, but it has no guts. A little door flips open and you put in maybe a class CC fuse inside and shut the door.

 

[electricalperson]

I can take some. I've got some new, on the shelf in boxes, but not here at home. They looked like a regular QO breaker, but it has no guts. A little door flips open and you put in maybe a class CC fuse inside and shut the door.

must be similar as these except QO style

 

[mdshunk]

must be similar as these except QO style[/IMG]

Yes, exactly. I'm pretty sure I have them in new boxes yet, so I should be able to get a part number. They don't seem to be in the SqD catalog anymore, so who know's how long ago they were discontinued.

 

[electricalperson]

Yes, exactly. I'm pretty sure I have them in new boxes yet, so I should be able to get a part number. They don't seem to be in the SqD catalog anymore, so who know's how long ago they were discontinued.

wonder what they were designed to protect

 

[mdshunk]

wonder what they were designed to protect

They were for a specific job that involved a really high AIC. Wasn't my idea.

 

[jim dungar]

I can take some. I've got some new, on the shelf in boxes, but not here at home. They looked like a regular QO breaker, but it has no guts. A little door flips open and you put in maybe a class CC fuse inside and shut the door.

I think they went obsolete back in the mid 70's. I believe they did not have a very high AIC (maybe as low as 5k). The door didn' flip open it pulled out. And I think the part number began with QF.

 

[mdshunk]

I think they went obsolete back in the mid 70's.

I know I didn't buy them when I was in elementary school, so they must have been available after that. I suppose stuff like that might stick around on shelves for a while. Pulling out does ring a bell though. Like a little drawer. Been a long time since I looked at them.

 

[necnotevenclose]

I am curious, why do you need a 100% fusible panelboard especially one with a fusible main?

Jim,

I guess I have to ask why wouldn?t you want to have a panelboard with a built-in main fuse? For emergency and legally required loads I have always tried to show on the secondary side of a transformer a fusible disconnect with a MLO panelboard downstream of that. I have run into several applications (as have probably must people) where the electrical room?s wall space is taken up by external protection. I was hoping that someone has integrated this into protection into one box.

 

[jim dungar]

Jim,

I guess I have to ask why wouldn?t you want to have a panelboard with a built-in main fuse? For emergency and legally required loads I have always tried to show on the secondary side of a transformer a fusible disconnect with a MLO panelboard downstream of that. I have run into several applications (as have probably must people) where the electrical room?s wall space is taken up by external protection. I was hoping that someone has integrated this into protection into one box.

The request was specifically for a 100% rated main fuse. In most cases even your separate fusible disconnect is not 100% rated.

 

[jim dungar]

OT for inquiring minds

OT for inquiring minds

I know I didn't buy them when I was in elementary school, so they must have been available after that.

Square D QFT units were rated 100,000AIC. They were pullout design for use with type SC/Class G fuses. Each housing held (2) fuses so they actually were tandem units.

Square D also had a type QFSB which combined a type SC pullout fuse and a toggle switch for lighting panels.

The last catalogs I have seen were dated 1968. I don't know when the last "parts" were sold.

 

[RHJohnson]

Used lots of those little fuses in DCS cabinets - separately fuse outputs to field instruments, so you wouldn't blow the main fuse and shut down the power plant! Bought and installed in the late 90's, but don't remember the mfg.

 

[Pierre C Belarge]

Here is an older version of what you are discussing. These panels are all live and operating (no pun intended, as these are located in a hospital)

 

[cschmid]

man I think in the storage shed I might still have an old fuse panel..that has pull out main and screw in fuses..I might have to go dig around and see just to have pic of it..:grin: I have no clue as to why I would save an antique like that..I did an upgrade years back and If I remember correctly I was impressed it was in such good shape..probabully not now I don't think I have even looked at it in 10yrs..