ENVIRO-TEC
15
FORM ET115.24-NOM1 (
519
)
ELECTRICAL CALCULATIONS INFORMATION
1. Calculate FLA = [(Motor Amps)*(Motor Qty) + (Heater Amps)]
2. Calculate MCA = [(1.25)*(FLA)]
3. Calculate MOP = [(2.25)*(1
st
Motor Amps) + (2
nd
Motor Amps) + (Heater Amps)]
a. If the calculated MOP is within 10% of the next smaller available fuse size, that fuse size shall be used. If the calculated
MOP is not within 10% of the next smaller available fuse size, the next larger fuse size above the calculated MOP must
be used.
b. If the selected MOP is smaller than the MCA, the selected MOP must be increased to the next larger available fuse size
above the MCA.
4. Non-Fused Door Interlock Disconnect Switch shall be sized according to MCA.
5. Fused Door Interlock Disconnect Switch and Main Fusing shall be sized according to MOP.
Available fuse sizes: 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 and 90.
MCA and MOP calculations are based on requirements from ANSI UL 1995 2nd Edition – CAN/CSA C22.2 No. 236-M90 Standard
for Safety; Heating and Cooling Equipment, which incorporates rules from NFPA 70 National Electric Code 2002 edition
.
NOTES:
1. Shaded areas indicate kW and voltage options not available.
2. Available voltages are single phase, 60 hertz.
3. Heaters over 48 AMPs are subdivided and fused per NEC.
Electric Heat Selection Chart
(AMPs)
M B H
6.8
8.5
10.2
11.9
13.7
17.1
20.5
23.9
27.3
30.7
34.1
41.0
47.8
KW
2.0
2.5
3.0
3.5
4.0
5.0
6.0
7.0
8.0
9.0
10.0
12.0
14.0
VOLTS
115
17.4
21.8
26.1
30.5
34.8
208
9.6
12.0
14.4
16.8
19.2
230
8.7
10.9
13.1
15.2
17.4
277
7.2
9.0
10.8
12.6
14.4
115
17.4
21.8
26.1
30.5
34.8
43.5
208
9.6
12.0
14.4
16.8
19.2
24.1
28.9
230
8.7
10.9
13.1
15.2
17.4
21.8
26.1
277
7.2
9.0
10.8
12.6
14.4
18.1
21.7
115
17.4
21.8
26.1
30.5
34.8
43.5
208
9.6
12.0
14.4
16.8
19.2
24.1
28.9
33.7
230
8.7
10.9
13.1
15.2
17.4
21.8
26.1
30.5
277
7.2
9.0
10.8
12.6
14.4
18.1
21.7
25.3
115
34.8
43.5
208
19.2
24.1
28.9
33.7
38.5
43.3
230
17.4
21.8
26.1
30.5
34.8
39.2
277
14.4
18.1
21.7
25.3
28.9
32.5
115
34.8
43.5
208
19.2
24.1
28.9
33.7
38.5
43.3
48.1
230
17.4
21.8
26.1
30.5
34.8
39.2
43.5
277
14.4
18.1
21.7
25.3
28.9
32.5
36.1
115
34.8
43.5
208
19.2
24.1
28.9
33.7
38.5
43.3
48.1
57.7
230
17.4
21.8
26.1
30.5
34.8
39.2
43.5
52.2
277
14.4
18.1
21.7
25.3
28.9
32.5
36.1
43.3
115
34.8
43.5
208
19.2
24.1
28.9
33.7
38.5
43.3
48.1
57.7
230
17.4
21.8
26.1
30.5
34.8
39.2
43.5
52.2
277
14.4
18.1
21.7
25.3
28.9
32.5
36.1
43.3
115
34.8
43.5
208
19.2
24.1
28.9
33.7
38.5
43.3
48.1
57.7
67.3
230
17.4
21.8
26.1
30.5
34.8
39.2
43.5
52.2
60.9
277
14.4
18.1
21.7
25.3
28.9
32.5
36.1
43.3
50.5
UNIT
SIZE
AMPS
20
06
08
10
12
14
16
18
