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5–Circuit Breaker (CB1, CB2, and CB3)
(208/230 volt only)
Line voltage connections are made to circuit breakers
CB1, CB2, and CB3 in the electric heat sections with
circuit breakers (designated by CB in the model num-
bers). Table 12 shows the amp rating for each circuit
breaker used. Single phase electric heat uses two pole
circuit breakers; while three phase electric heat uses
three pole circuit breakers.
TABLE 12
ECB29 CIRCUIT BREAKERS
UNIT
CB1
AMPS
CB2
AMPS
CB3
AMPS
ECB29-5CB-1 (P) 30 AMP ––– –––
ECB29-8CB-1 (P) 50 AMP ––– –––
ECB29-10CB-1 (P) 60 AMP ––– –––
ECB29-12.5CB-1 (P) 25 AMP 50 AMP –––
ECB29-15CB-1 (P) 30 AMP 60 AMP –––
ECB29-20CB-1 (P) 60 AMP 60 AMP –––
ECB29-25CB-1 (P) 50 AMP 50 AMP 50 AMP
ECB29-30CB-1 (P) 60 AMP 60 AMP 60 AMP
ECB29-15CB-1 (Y) 60 AMP ––– –––
ECB29-20CB-1 (Y) 40 AMP 35 AMP –––
ECB29-25CB-1 (Y) 50 AMP 35 AMP –––
Note: Do not remove patch plate or insulation on units
without circuit breakers!!
6–Fuse (F3) (460 and 575 volt only)
Line voltage connections are made to fuse (F3) in
all 460 and 575 volt electric heat sections. Three
fuses are mounted in the fuse block. The electric
heat name plate and Table 13 show the amp ratings
for the fuses used.
TABLE 13
ECB29 460/575 VOLTAGE FUSES
UNIT FUSE SIZE (AMPS)
ECB29-10-1 (G) 20 AMP
ECB29-15-1 (G) 25 AMP
ECB29-20-1 (G) 35 AMP
ECB29-25-1 (G) 40 AMP
ECB29-20-1 (J) 25 AMP
ECB29-25-1 (J) 35 AMP
7–Terminal Strip (TB2) 208/230 volt only)
For the electric heat sections without circuit breakers
or fuses, line voltage connections are made to
terminal strip TB2. The terminal strip is located in the
lower left corner of the electric heat vestibule panel.
Single phase electric heat uses two pole terminal
strips; while three phase electric heat uses three pole
terminal strips.
8–Heating Elements (HE1 through HE6)
Heating elements are composed of helix wound
bare nichrome wire exposed directly to the air-
stream. The elements are supported by insulators
mounted to the wire frame. For single phase ap-
plications, one element is used per stage. Each
stage is energized independently by the corre-
sponding relay located on the electric heat vesti-
bule panel. All three phase heating elements are
arranged in a three phase delta. Once energized,
heat transfer is instantaneous. High temperature
protection is provided by primary and secondary
high temperature limits.
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