Are there instances you use a non-fused disconnect?

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fuse vs non-fuse

fuse vs non-fuse

Kinda a "tiger by the tail" issue for you, Amanda. As others have stated, unless you know all the specs about the load served, it can change from "danged contractor/electrician" to "danged designer/engineer".

If you unit requires protection by fuse only and you spec non-fuse...bad call.....if the load doesn't specify and you go fusible....somewhat bad call ($$ wise).

From my experience, the equipment installed does not alays match what was spec'ed so fusible is probaly a safe call. If the unit requires fuses, you are ready and if the unit requires a lower overcurrent protection than the breaker provides, you have that covered too.

I see a lot of plans that call for 30 amp or 60 amp circuits to RTUs and, once they are in place, the max OCP turns out to be less. It a matter of perference, but many electricians I meet rather just install the proper fuse rather than have to change out the breaker. (The units often require "odd" size overcurrent protection which is more readily available off the shelf as a fuse than as a breaker)
 
For my own self, another take I have on the subject is when installing for outdoor units at grade level I try to consider access for children to live components like busbars and fuse clips etc. A simple safety switch may meet code for a compressor mounted at the side of a residence, but unless a padlock is installed, any 10 year old curious kid with a touch of AHHD is a potential risk. So I try to use the type that needs to be accessed with a screwdriver, or I put in a 3R loadcenter and a breaker rated for hvac.
 
augie47 said:
(The units often require "odd" size overcurrent protection which is more readily available off the shelf as a fuse than as a breaker)

Interesting...could you site an example?

The units that I wire invariably specify both a minimum circuit ampacity (mca) and a maximum overcurrent protective device (mopd). I can always find a standard value CB to fit within those limits.
 
CB availability

CB availability

Depending on the mfg and the breaker types, 25, 35 amp and 45 amp breakers are not often on the shelf in this area, especially in a bolt-in or higher interuppting capacity.
 
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