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hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I have condensing unit which power indoors unit fans, heaters for refrigeration.

From CU unit I have 4-#12, 4-#12, 4-#10 in 1” conduit.


Asked for overcurrent protection and more than 3 current carrying conductors calculation to check ampacity of cable and was told 310.1 scope of this article does not apply to conductors that form integral part of equipment by electrician.

Would 310 scope not apply to above situation or 310.1 is talking about something else?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Read the entire section (310.1) ..."such as........................"
"integral part of equipment:" does not apply to coindcutors you install to feed the equipment.
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Read the entire section (310.1) ..."such as........................"
"integral part of equipment:" does not apply to coindcutors you install to feed the equipment.

Right so CU units and indoor units are two separate units. Wiring between them would not be in scope of 310.1?


Sent from my iPhone using Tapatalk
 

kwired

Electron manager
Location
NE Nebraska
I have condensing unit which power indoors unit fans, heaters for refrigeration.

From CU unit I have 4-#12, 4-#12, 4-#10 in 1” conduit.


Asked for overcurrent protection and more than 3 current carrying conductors calculation to check ampacity of cable and was told 310.1 scope of this article does not apply to conductors that form integral part of equipment by electrician.

Would 310 scope not apply to above situation or 310.1 is talking about something else?
Unless the wiring method between indoor and outdoor unit is a listed assembly intended to be used for that specific application, art 310 should apply.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Unless the wiring method between indoor and outdoor unit is a listed assembly intended to be used for that specific application, art 310 should apply.
I agree. If these are all 3 phase circuits you'll end up with 9 CCC's.
 

kwired

Electron manager
Location
NE Nebraska
I agree. If these are all 3 phase circuits you'll end up with 9 CCC's.
he has 8 - #12 and 4-#10. Unless someone pulled three EGC's or there is three neutrals involved there is probably 12 current carrying conductors.

My guess - the 12's are for evap fans and the 10's are for defrost heaters. They possibly are already have had ampacity corrections, never ran into evap fan circuit that needed to be more than a 15 amp circuit, defrost heaters maybe ran into some that are over 20 amps but most are under 20 that I have seen.

Add: could be some control conductors in there as well. Typical to have a pair for the "room thermostat" as well as a pair for defrost termination thermostat.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
he has 8 - #12 and 4-#10. Unless someone pulled three EGC's or there is three neutrals involved there is probably 12 current carrying conductors.

That's why I said 3 phase, even if there is a neutral or EGC in each circuit it's still only 9 CCC's.
 

jap

Senior Member
Occupation
Electrician
Not enough info to be able to guess.

I'd bet there's more than 9 CCC's.

He may have (1) 3ph circuit with the #10's along with a shared #10 EGC for all, (2) 3ph circuits and (1) 1ph circuit with the #12's,
or
all (6) coud be 1ph circuits with no EGC
or
Who knows how many CCC's there are with this number of conductors not knowing what they're function is.


JAP>
 

kwired

Electron manager
Location
NE Nebraska
Not enough info to be able to guess.

I'd bet there's more than 9 CCC's.

He may have (1) 3ph circuit with the #10's along with a shared #10 EGC for all, (2) 3ph circuits and (1) 1ph circuit with the #12's,
or
all (6) coud be 1ph circuits with no EGC
or
Who knows how many CCC's there are with this number of conductors not knowing what they're function is.


JAP>
I have condensing unit which power indoors unit fans, heaters for refrigeration.

From CU unit I have 4-#12, 4-#12, 4-#10 in 1” conduit.


Asked for overcurrent protection and more than 3 current carrying conductors calculation to check ampacity of cable and was told 310.1 scope of this article does not apply to conductors that form integral part of equipment by electrician.

Would 310 scope not apply to above situation or 310.1 is talking about something else?
Still speculation but sounds typical for a commercial refrigeration (walk-in, retail display, or similar) where the evaporator unit has at very least some control conductors between it and the condenser unit that are typically 120 - 480 volts. Many cases of 208-240 volts and 30 amp or less often are supplied by same circuit as the condenser unit, defrost heaters are interlocked so they don't run at same time as the compressor - possibly the 10 AWG conductors, the 12's might be just controls or even controls plus evaporator fans, or even door frame heaters or such.
 
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