York YPAL 051 User Manual

JOHNSON CONTROLS

FORM 100.50-NOM6 (1207)

Field wiring to the unit must conform to provisions 
of National Electrical Code (NEC) ANSI / NFPA 70-
Lat est Edition and / or local ordinances. The unit must 
be electrically grounded in accordance with the NEC 
and / or local codes. Voltage tolerances, which must be 
main tained during starting and running con di tions,  are 
in di cat ed on the unit data plate.

The internal wiring harnesses furnished with this unit 
are an integral part of the design certifi ed unit. Field 
al ter ation to comply with electrical codes should not 
be required. If any of the wire supplied with the unit 
must be replaced, replacement wire must be of the type 
shown on the wiring diagram and the same minimum 
gauge as the replaced wire.

Power supply to the unit must be NEC Class 1 and must 
comply with all applicable codes. A disconnect switch 
must be provided (factory option available). The switch 
must be separate from all other cir cuits. Wire entry at 
knockout openings re quires conduit fi ttings to comply 
with NEC and/or Local Codes. 

Electrical service re quired for the cool ing only eco

2

 

roof top, use the ap pro pri ate  cal cu la tions  listed  below 
from U.L. 1995. Based on the op er at ing  mode  and 
con fig u ra tion  of  the  roof top, the cal cu la tions  will 
yield dif fer ent MCA (minimum cir cuit am pac i ty),  and 
MOP  (max i mum  overcurrent  protection).  MCA and 
Overcurrent  Pro tec tion  De vice Data is supplied on 
the unit data plate. Also refer to Table 2-7, 2-9, 2-10, 
2-11, 2-12, 2-13 and 2-14, Electrical Data. 

The following calculations apply to electrical data for 
the rooftop unit. All con cur rent  load  con di tions  must 
be con sid ered in the cal cu la tions, and you must use the 
highest value for any com bi na tion  of  loads.

Minimum Circuit Ampacity (MCA) is based on 125% 
of the rated load amps for the largest mo tor plus 100% 
of the rated load amps for all other loads in clud ed  in  the 
circuit, per N.E.C. Article 440-34. 

The minimum rec om mend ed  disconnect  switch  is  based 
on 115% of the rated load amps for all loads in clud ed 
in the circuit, per N.E.C. 

Maximum overcurrent protection is based upon 225% 
of the rated load amps for the largest motor plus 100% 
of the rat ed load amps for all other loads in clud ed  in 
the cir cuit, per N.E.C. Article 440-22. If the max i mum 
overcurrent pro tec tion does not equal a stan dard cur rent 
rating of an overcurrent protective device, then the 
marked max i mum rating is to be the next lower stan dard 
rating. How ev er, if the de vice se lect ed  for  maximum 
overcurrent protection is less than the MCA, then se lect 
the lowest standard max i mum fuse size great er than or 
equal to the MCA.

Figures 2-9, 2-10 & 2-11 show the power wiring that 
must be fi eld sup plied and installed. See Table 2-16 for 
the allowable conductor wire size for the electrical lugs 
in the unit.

For dual point power connections, TB1 in the pow er 
panel supplies the all unit com pres sors  and  con dens er 
fans. TB2 in the power panel sup plies pow er to the unit 
supply, return and exhaust fans, and control cir cuit ry.