Forgot a term or phrase

There is something which I am trying to remember from my working days. I an electrical protection scheme, fuses were protected by fuses. There was a term or phrase we referred to this but it has totally left my old head.

Can anyone help out?

Perhaps you are thinking about trigger fuses which indicate when the main fuse blows.

This is frustrating. It had to do with synchronizing the order in which the fuses were to blow.

Getting old stinks!

Perhaps fast blow and slow blow? Perhaps a lower current slow blow in series with a higher current fast blow?

Thanks zoomkat. All I can come up with is "fuse coordination" but this isn't exactly it either.

I'll be satisfied with this phrase, now I can put it to rest.

Progressive circuit protection. It means to apply fuses and/or circuit breakers in such a way as the closest protection up-stream from the fault goes first. This allows circuits to feed multiple loads but only trip out the faulted load. Think of it this way... you plug a bad lamp into a outlet and the circuit breaker to the outlet blows but the rest of the house still has power, this is progressive protection.

R

Sounds like "redundancy." But I can't picture protecting a fuse with a fuse because the object is to get the fuse to blow. You don't want to protect it.

Thanks all for your suggestions.

I guess the phase is "Fuse Coordination" after all.

Fuse Coordination

.

charliesixpack: I can't picture protecting a fuse with a fuse because the object is to get the fuse to blow. You don't want to protect it.

When do you stop? A fuse for the fuse's fuse's fuse's fuse?

I'm an advocate of fence wire, myself.

;) <<<<<< smiley just in case any thinks I'm serious.

Getting old stinks!

Maybe, but being old has it's advantages. (right Russel ?) ;D

Fuse Selective Coordination

fuse coordination

Truthfully, I'm not familiar with this concept but I would guess it relates to the time delay between fuses in the power distribution chain and the time elapsed from when the local fuse blows until the next fuse in up the chain blows.

just a guess.

Getting old stinks but, does beat the alternative ;)

Speak for yourself. I'm not getting older. I'm getting better... ;D

I must admit, I wouldn't want to repeat High School ! :D

Cascading fault protection (breaker failure relaying) is used when breakers fail to open and clear a fault and upstream breakers are signaled to open.

I'm not familiar with this concept

The concept of getting old?

JimboZA: When do you stop? A fuse for the fuse's fuse's fuse's fuse?

I'm an advocate of fence wire, myself.

;) <<<<<< smiley just in case any thinks I'm serious.

I've worked on gear I later found out to be "protected" by the proverbial rusty nail {{{shudder}}}

The concept of getting old?

ha , ha, ha, very funny. Yeah, that too. ;D (actually I meant "progressive protections"). It's like Power Factor Correction, it's one of those things you don't normally have to think about because someone else (another department or agency) handles it. Usually both are part of the building design for a large facility and they don't have to worry about it unless they make some major changes. It takes a lot of experience to design the progressive protection or cascading fuse protection schemes. I would expect it to be a senior electrical engineer with at least 20 yrs experience.