Carrier NP034-074 specifications Field Power Wiring Connections

Use care when drilling into corner post to avoid damage to con- denser coil.

Fig. 17 Ð Disconnect Location, 054-074 Units

(50 Series Horizontal Discharge Shown)

POWER WIRING Ð Units are factory wired for the voltage shown on the unit nameplate. The main terminal block is suitable for use with aluminum or copper wires. Maximum wire size is 3/0 AWG (American Wire Gage).

Use the following formula to determine the percent voltage imbalance.

% Voltage Imbalance

= 100 x max voltage deviation from average voltage

When installing units, provide a disconnect per NEC (National Electrical Code) of adequate size (MOCP [Maxi- mum Overcurrent Protection] of unit is on the informative plate). All ®eld wiring must comply with NEC and all local codes. Size wire based on MCA (Minimum Circuit Amps) on the unit informative plate. See Fig. 18 for power wiring connections to the unit power terminal block and equipment ground.

Operating voltage to the compressor must be within the voltage range indicated on the unit nameplate. Voltages be- tween phases must be balanced within 2%, and the current must be balanced within 10%. See Tables 3-7 for unit elec- trical data.

	LEGEND
EQUIP	Ð Equipment
GND	Ð Ground
NEC	Ð National Electrical Code
TB	Ð Terminal Block

Fig. 18 Ð Field Power Wiring Connections

average voltage

Example: Supply voltage is 460-3-60.

AB = 452 v

BC = 464 v

AC = 455 v

Average Voltage =	452 1 464 1 455
		3
=	1371
	3
= 457

Determine maximum deviation from average voltage:

(AB) 457 ± 452 = 5 v (BC) 464 ± 457 = 7 v (AC) 457 ± 455 = 2 v

Maximum deviation is 7 v.

Determine percent voltage imbalance:

% Voltage Imbalance = 100 x	7
	457
= 1.53%

This amount of phase imbalance is satisfactory as it is be- low the maximum allowable 2%.

IMPORTANT: If the supply voltage phase imbalance is more than 2%, contact local utility immediately.

Unit failure as a result of operation on improper line volt- age or excessive phase imbalance constitutes abuse and may cause damage to electrical components.

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