overload protection on air condensing unit

Status
Not open for further replies.

kitsr

Member
AHJ requesting overload protection on ac condensor. Never been required to do this on ac unit.
The unit min cir amp is 23 amps, max cir breaker 40 amp.
RLA on compressor is 17.5 amps.
Does 440.52 (3) apply ? Is this required by code?
I used a 30 amp 2-pole switch as my disc. motor rated.
If 440-52(3) applies can I change the breaker to a 25 amp to meet this?
Any help or comments are appreciated.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The overload protection should be part of the unit.
If it is a factory unit with a NRTL listing, all you or the inspector should be concerned about is the MCA and Max OCP per 440.22(C)
 

Smart $

Esteemed Member
Location
Ohio
AHJ requesting overload protection on ac condensor. Never been required to do this on ac unit.
The unit min cir amp is 23 amps, max cir breaker 40 amp.
RLA on compressor is 17.5 amps.
Does 440.52 (3) apply ? Is this required by code?
I used a 30 amp 2-pole switch as my disc. motor rated.
If 440-52(3) applies can I change the breaker to a 25 amp to meet this?
Any help or comments are appreciated.
440.52 applies... but overload protection is usually built into most condensor units. You'd have to refer to the schematic to verify. Lacking a schematic, check the documentation, and short of that, contact the manufacturer...
 

Smart $

Esteemed Member
Location
Ohio
The overload protection should be part of the unit.
If it is a factory unit with a NRTL listing, all you or the inspector should be concerned about is the MCA and Max OCP per 440.22(C)
Is listing all that is necessary to verify integrated overload protection?
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Your inspector is confused. The overload is internal to the unit. Your breaker is to protect your wire from a dead short or locked up compreser. The unit tells you min circuit amps to select wire and breaker size to comply with code. If you met this your legal. I always use the highest breaker size allowed by name plate. That saves you service calls for tripped breaker.
 

Buck Parrish

Senior Member
Location
NC & IN
I agree with the guys above.
Your name plate would allow you to use #12 wire protected by a 40 amp breaker. Tell your inspector. The overload protection is built in to the unit.

You must use an HCAR breaker type.
 

kwired

Electron manager
Location
NE Nebraska
Is listing all that is necessary to verify integrated overload protection?

Wouldn't that depend on what the criteria is for receiving the listing?

I don't know what listing requirements are but have never seen a combination condenser/compressor unit that does not have overload protection installed as part of the unit. Stand alone compressor or condenser you see all kinds of things, especially on older units.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Wouldn't that depend on what the criteria is for receiving the listing?

I don't know what listing requirements are but have never seen a combination condenser/compressor unit that does not have overload protection installed as part of the unit. Stand alone compressor or condenser you see all kinds of things, especially on older units.

Agree.
In my post (#2), I may assume too much with the listing, but, as you state, I have never seen combination compressor/condenser which did not have overload protection and they have all been listed and show MCA and Max OCP.
In the big ole world out there, some may exists that don't have O.L., but, my point is, I think most inspectors, once they see a listing with those requirements met, are satisfied.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Agree.
In my post (#2), I may assume too much with the listing, but, as you state, I have never seen combination compressor/condenser which did not have overload protection and they have all been listed and show MCA and Max OCP.
In the big ole world out there, some may exists that don't have O.L., but, my point is, I think most inspectors, once they see a listing with those requirements met, are satisfied.

I think that this is a time when you can assume. :)
 

Smart $

Esteemed Member
Location
Ohio
I agree. I have not come across a hermetic A/C compressor without an internal overload.
I can accept the assumption as well myself... but why not the inspector in the OP case? I realize we cannot answer this question, and thus the reason I gave the avenues of verification in my first post here.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I can accept the assumption as well myself... but why not the inspector in the OP case? I realize we cannot answer this question, and thus the reason I gave the avenues of verification in my first post here.

Even inspectors have learning curves.
One reason most of us are here.
 
Status
Not open for further replies.
Top