Grid Tie 100 amp AC Safety Shutoff Switch - what size fuses?

[PoPoShoo]

The Inverter output is 47.5 amps. Would I use the 100 amp fuses or go down to 60 amps?

The Safety Switch is a Siemens GF223NR

Also, what fuse class to use: H, K or R?

 

[timselectric]

R class are general standard fuses.
Good for most situations.

 

[timselectric]

And 60 amp with fuse reducers.

 

[PoPoShoo]

And 60 amp with fuse reducers.

Tim, I'm having a brainfart...what is a fuse "reducer"?

 

[timselectric]

Tim, I'm having a brainfart...what is a fuse "reducer"?

A 100 amp disconnect has 100 amp fuses holders. They can accept fuse sizes of 65 to 100 amp. You need reducers to accept fuses for a 60 amp fuse holder. Which will accept 35 to 60 amp fuses.

 

[timselectric]

Like this

COOPER BUSSMAN BUSS 216 FUSE REDUCER 60 AMP 250V TO 100A CLIPS NEW | eBay

We are always buying!

www.ebay.com

 

[PoPoShoo]

THNX Tim!! I'll probably just bump up to 65 amp fuses

 

[timselectric]

The inspector probably won't notice it as a problem. Because the wire is so large.

 

[PoPoShoo]

or Tim, would there be any harm in 100 amp fuses? I'm finding that the class R 65-amp fuses are hard to find and expensive

 

[timselectric]

100 amp would give you no overcurrent protection.
(The wire becomes the weakest link)
It would only provide short protection.

 

[timselectric]

If you already have overcurrent protection at the array, you could argue that you only need short protection at the disconnect. But, it would be a hard sell.

 

[Chris72]

Is it ok to use 125 amp braker to a 100a non fused 100% duty double throw manual transfer switch to 125 amp main breaker sub panel?
Also does anybody have any recommendations on solar ready 200a main meter combo panels that will accommodate CTs?