Table of Contents
Advertisement
Fig. 41 — Mounting Position for Field Disconnects
(up to 100A)
Field power wires are connected to the unit at line-side pres-
sure lugs at the main terminal block (TB1) or at factory-
installed option non-fused disconnect switch. Max wire size is
#2 AWG (copper only). See Fig. 29.
NOTE: TEST LEADS - Unit may be equipped with short leads
(pigtails) on the field line connection points off the optional
disconnect switch. These leads are for factory run-test purposes
only; remove and discard before connecting field power wires
to unit connection points. Make field power connections direct-
ly to line connection pressure lugs only.
WARNING
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire. (See Fig. 42.)
ELECTRIC
DISCONNECT
SWITCH
WIRE ONLY
Fig. 42 — Disconnect Switch and Unit
All Units — All field wiring must comply with the NEC and
local requirements.
Size wire based on MCA (Minimum Circuit Amps) on the
unit informative plate. See Fig. 43 and the unit label diagram
for power wiring connections to the unit power terminal blocks
and equipment ground. Maximum wire size is 2/0 AWG per
pole.
Provide a ground-fault and short-circuit over-current protec-
tion device (fuse or breaker) per NEC Article 440 (or local
COPPER
ALUMINUM
WIRE
codes). Refer to unit informative data plate for MOCP (Maxi-
mum Over-current Protection) device size.
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. On 3-phase
units, voltages between phases must be balanced within 2%
and the current within 10%. Use the formula shown below to
determine the percent of voltage imbalance.
max voltage deviation from average voltage
= 100 x
Example: Supply voltage is 230-3-60.
AB = 224 v
BC = 231 v
AC = 226 v
224 + 231 + 226
Average Voltage =
681
=
=
227
Determine maximum deviation from average voltage.
(AB) 227
224 = 3 v
–
(BC) 231
227 = 4 v
–
(AC) 227
226 = 1 v
–
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100 x
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact your local electric utility company immedi-
ately.
All units except 208/230-v units are factory wired for the
voltage shown on the nameplate. If the 208/230-v unit is to be
connected to a 208-v power supply, the control transformer
must be rewired by moving the black wire with the
male spade connector from the 230-v connection and moving it
to the 200-v
1
/
-in. male terminal on the primary side of the
4
transformer. Refer to unit label diagram for additional informa-
tion.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment dam-
age.
Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to
electrical components. Such operation would invalidate
any applicable Bryant warranty.
NOTE: Check all factory and field electrical connections for
tightness.
Units Without Factory-Installed Disconnect — When in-
stalling units, provide a disconnect switch of adequate size per
NEC (National Electrical Code). Disconnect sizing data is pro-
vided on the unit informative plate. Locate on unit cabinet or
within sight of the unit per national or local codes. Do not cov-
er unit informative plate if mounting the disconnect on the unit
cabinet.
Units with Factory-Installed Disconnect — The factory-in-
stalled option disconnect switch is located in a weatherproof
enclosure located under the main control box. The manual
25
average voltage
3
3
4
226
= 1.76%
CAUTION
1
/
-in. fe-
4
Advertisement
Table of Contents
