Cable current limiting fuses

[mooreaaryan]

Good morning all,

I am looking for a solution on cable current limiting fuses and how it works. We are tying in to an MCC bussing. We have had the bus flags made now we are looking for the fuses. Does someone make a fuse that we can’t take the cable feed through the bottom of fuse and secure it (crimp or lug screw like a DLO lollipop) that has a two hole paddle on opposite side. I’ve asked my supply house they are not to for sure I would. Just hoping someone has had this idea in the past

Thank you have a great Tuesday

 

[Todd0x1]

Are you talking about cable limiters? They make them with a crimp on one side and 2 hole lug on the other side.

Or are you talking about actual fuses?

 

[mooreaaryan]

Are you talking about cable limiters? They make them with a crimp on one side and 2 hole lug on the other side.

Or are you talking about actual fuses?

Cable limiters. I cannot find any any where for 12 to 21 week insane world we are living in I was ignorant that, although the function is the same, the name is different Thank you

 

[petersonra]

What is the function of cable limiters anyway?

 

[texie]

I'm curious why the OP is trying to use cable limiters. These have very limited applications, typically used on service entrance conductors that are in parallel to help detect and prevent overloading of other conductors from an open conductor.

 

[petersonra]

I'm curious why the OP is trying to use cable limiters. These have very limited applications, typically used on service entrance conductors that are in parallel to help detect and prevent overloading of other conductors from an open conductor.

Is that a common problem?

Wouldn't that amount to fuses in parallel?

 

[augie47]

What is the function of cable limiters anyway?

https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/bussmann-series-supplemental-fuses/cable-limiters/bus-ele-ds-1042-uh-k-cable-limiters.pdf

 

[mooreaaryan]

I'm curious why the OP is trying to use cable limiters. These have very limited applications, typically used on service entrance conductors that are in parallel to help detect and prevent overloading of other conductors from an open conductor.

Yep that’s why the engineer want them there

 

[jim dungar]

Wouldn't that amount to fuses in parallel?

No.
The load side of each limiter is connected to its own conductor therefore it is not directly in parallel with any other limiter.

 

[petersonra]

No.
The load side of each limiter is connected to its own conductor therefore it is not directly in parallel with any other limiter.

How are these not in parallel?

 

[augie47]

I think the term "fuse" as we commonly look at them is a misnomer as they are not actually rated in amps.
From the description:
Unlike fuses, cable limiters are selected by cable
size rather than amp rating, e.g., a “4/0” limiter
will carry the current of a 4/0 cable.

 

[jim dungar]

How are these not in parallel?

View attachment 2561988

Are both ends of the limiters connected together? you have drawn a parallel circuit of series components.
Yes the paths are in parallel, but each individual limiter is only in series with a single impedance.

 

[synchro]

No.
The load side of each limiter is connected to its own conductor therefore it is not directly in parallel with any other limiter.

How are these not in parallel?

I think when Jim said "not directly in parallel" he meant that the current limiters would not be connected in close proximity, but instead through the full length of the run of parallel conductors. This is an important distinction because the resistance of the conductors acts as a "ballast" to equalize the current sharing through the current limiters, which would not be the case if they were paralleled directly right next to each other.

By the way, inside power semiconductors such as IGBT's, BJT's, MOSFET's etc, it is common to use metallization to form ballast resistors between the individual "cells" that are put in parallel, so that the current is shared more equally between them.

 

[jim dungar]

I think when Jim said "not directly in parallel" he meant that the current limiters would not be connected in close proximity, but instead through the full length of the run of parallel conductors. This is an important distinction because the resistance of the conductors acts as a "ballast" to equalize the current sharing through the current limiters, which would not be the case if they were paralleled directly right next to each other.

Each limiter only sees 100% of the current flowing through the single conductor it is connected to.