A/C Disconnect

[frank_n]

Is there a code that requires an A/C disconnect to be fusible?

Frank

 

[infinity]

Nope, it's merely there to allow someone to work on the unit while de-energized.

 

[qcroanoke]

Is there a code that requires an A/C disconnect to be fusible?

Frank

No, Overcurrent/short circuit protection is required at where the circuit begins.
The disconnect at the unit is not required to be fused by the NEC.

 

[frank_n]

Thanks for the quick reply. Sometimes a A/C compressor states that fuses are required on the nameplate. I was wondering if it was a code requirement too.

Frank

 

[kwired]

Thanks for the quick reply. Sometimes a A/C compressor states that fuses are required on the nameplate. I was wondering if it was a code requirement too.

Frank

When fuses are required it is convenient to place them at the local disconnecting means - but nothing says they have to be at that location.

 

[infinity]

Thanks for the quick reply. Sometimes a A/C compressor states that fuses are required on the nameplate. I was wondering if it was a code requirement too.

Frank

Even if the unit required "fuse only" protection you still would not be required to use a fused disconnect at the unit. That fuse protection could be elsewhere in the circuit.

 

[cowboyjwc]

But if you don't use a fused disconnect and the name plate says "Max OCP 25 amps" then you would need to install a 25 amp breaker at the panel.

 

[GoldDigger]

Or maybe even a smaller breaker if applying the HP to current tables and the Code FLA multipliers came up with a smaller number than the specific number for that motor, right?

Tapatalk!

 

[cowboyjwc]

440.12(A) says that you use the name plate rated load current or branch circuit selection current, whichever is greater.

 

[ron]

I realize we are likely speaking about small HVAC equipment, but just for completness, if the local switch will have higher than 5kA worth of short circuit current (large circuits), you will need fuses to get the short circuit rating of the switch (now fusable switch) to be adequate.

 

[iwire]

Thanks for the quick reply. Sometimes a A/C compressor states that fuses are required on the nameplate. I was wondering if it was a code requirement too.

Frank

In that case you are required to use fuses in the circuit. The location is up to you but from a practical standpoint if you are coming out of a breaker panel using a fused disconnect at the unit is the most cost effective way to do it.