# 600 volt fuse vrs 250 volt fuse



## backstay (Feb 3, 2011)

More voltage means you need more physical separation between your energized parts. That what voltage ratings are about. 250 volt fuses cost less so why throw money away using 600 volt on 240 or less?


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## backstay (Feb 3, 2011)

There's more to fuses than amp ratings also. The fuse needs to be able to handle the available fault current also. Some are rated for DC, which is a whole deferent game.


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## Amish Electrician (Jan 2, 2010)

It's mainly a matter of cost.

Not only do the 600v fuses often cost more, but ...

There are different size fuses. If you're making a disconnect for 480, you need much greater clearances than you would need for 140. Hence, the enclosures cost a lot more, and are much larger.


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## MechanicalDVR (Dec 29, 2007)

Amish Electrician said:


> It's mainly a matter of cost.
> 
> Not only do the 600v fuses often cost more, but ...
> 
> There are different size fuses. If you're making a disconnect for 480, you need much greater clearances than you would need for 140. Hence, the enclosures cost a lot more, and are much larger.


 
Do you use those 140v fuses on the "D" phase???


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## Big John (May 23, 2010)

MechanicalDVR said:


> Do you use those 140v fuses on the "D" phase???


 That whole "D phase" business reminds me of this scene from Mr. Mom:





-John


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## John Valdes (May 17, 2007)

I use fuses rated for the current. Meaning if I have only 600 volt fuses, and the system is 240 but the current is the same, I have no issue using them.
I would try my very best to get the voltage and the current right. But in the end, if the current is right, I do not lose any sleep over the voltage.


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## Big John (May 23, 2010)

Assuming, of course, you wouldn't use a 250 volt fuse on a 600V system just because the amperage matches... :icon_eek:

-John


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## micromind (Aug 11, 2007)

The voltage rating of a fuse is the maximum voltage it can interrupt. It can be used on a lower voltage, and it'll work just fine. But it cannot be used on a higher voltage. 

As noted, the main reason you'd use a fuse rated at the system voltage is cost. A 20 amp 250 volt fuse is not very expensive, a 20 amp 15KV fuse costs a LOT more. Both will protect the circuit, but one is less money.


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## McClary’s Electrical (Feb 21, 2009)

Big John said:


> That whole "D phase" business reminds me of this scene from Mr. Mom:
> 
> 
> 
> ...


 

I have often wondered if that's where 220/221 got his name from:whistling2:


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