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AMPERAGE TABLE/OVERCURRENT
PROTECTION
This table provides the total connected heating element load in
amperes for branch circuit conductor and over current protection
sizing. Single-phase heaters are two wire circuits. Three-phase
heaters are three wire circuits. In addition to the foregoing a
ground conductor may be required.
The rating of the overcurrent protection should be computed on
the basis of 125 percent of the total connected load amperage.
Where the standard ratings and settings do not correspond with
this computation, the next higher standard rating or setting
should be selected.
HEATER CIRCUITS
The water heater's electrical components are pictured and
identified in Figure 1.
The following describes the heater circuits and includes wiring
diagrams. All heater circuits are designed for 60 hertz alternating
current.
STANDARD KW INPUTS
Standard
Immersion
KW
Heaters***
Ratings
No. Of Wattage 208V
3
1
6
1
9
1
12
1
12,000
15
1
15,000
18*
1
18,000
24
2
12,000
30
2
15,000
36*
2
18,000
45
3
15,000
54
3
18,000
60**
4
15,000
75**
5
18,000
90**
5
18,000
* 208V models use one additional immersion heater.
** Available on 50 gallon models or larger.
***Each immersion heater contains three electric elements.
Number of
50A Contractors
240V
480V
3,000
6,000
1
9,000
1
2
2
3
3
4
4
5
5
The heater is equipped with 120 volt control circuit where all of
the heating elements are switched on and off together. This is
the standard circuit and may be used with up to five elements.
The control circuit wiring is 14 AWG rated 600 volts, 105°C.
A low water cutoff switch is available as an optional safety device
to protect the elements from damage due to lack of water in the
heater.
Power circuit wiring is rated 600 volts, 75°C.
The following wiring diagrams are included in this manual to
show typical arrangement of electrical components in the control
and power circuits by voltage and phase characteristics. They
are to be used as a reference by the installer or servicer in
performing their work.
wiring is furnished with the heater.
Full Load Current In Amperes
Single Phase
208V
240V
277V
14.4
12.5
10.8
28.8
25.0
21.2
43.3
37.5
32.5
1
57.7
50.0
43.3
72.1
62.5
54.2
86.5
75.0
65.0
115.4
100.0
86.6
144.2
125.0
108.3
173.1
150.0
130.0
216.3
187.5
162.5
2
N/A
225.0
194.9
N/A
250.0
216.6
3
N/A
312.5
270.8
N/A
375.0
324.9
14
CONTROL CIRCUIT
POWER CIRCUIT
WIRING DIAGRAMS
An actual diagram of the water heater
Three Phase
480V
208V
240V
6.3
8.3
7.2
12.5
16.7
14.4
18.8
25.0
21.7
25.0
33.3
28.9
31.3
41.6
36.1
37.5
50.0
43.3
50.0
66.6
57.7
62.5
83.3
72.2
75.0
99.9
86.6
93.8
124.9
108.3
112.5
149.9
129.9
125
166.7
145
156
208.4
181
188
250
217
480V
3.6
7.2
10.8
14.4
18.0
21.7
28.9
36.1
43.3
54.1
65.0
72
90
108
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