Operating instructions
8
Installing the water heater.
NOTICE: This guide recommends minimum branch circuit sizing and wire size based on National Electric Code. Refer to 
wiring diagrams in this manual for field wiring connections.
Branch Circuit Sizing and Wire Size Guide
   Total Water      Recommended Over Current Protection  Copper Wire Size AWG Based  
   Heater Wattage      (fuse or circuit breaker amperage rating)  on N.E.C. Table 310-16 (75°C)
     208V 240V 277V 480V  208V 240V 277V 480V
    3,000    20  20  15  15    12  12  14  14
    4,000    25  25  20  15    10  10  12  14
    4,500    30  25  25  15    10  10  10  14
    5,000    30  30  25  15    10  10  10  14
    5,500    35  30  25  15    8  10  10  14
    6,000    40  35  30  20    8  8  10  12
    8,000    50  45  40  25    8  8  8  10
    9,000    –  50  45  25    –  8  8  10
   10,000    –  –  50  30    –  –  8  10
   11,000    –  –  50  30    –  –  8  10
   12,000    –  –   –  35    –  –  –  8
CAUTION: The presence 
of water in the piping 
and water heater does 
not provide sufficient 
conduction for a ground. 
Non-metallic piping, 
dielectric unions, flexible 
connectors etc. can cause 
the water heater to be 
electrically isolated.
Electrical Connections
A separate branch circuit with copper 
conductors, overcurrent protective device 
and suitable disconnecting means must be 
provided by a qualified electrician. 
All wiring must conform to local codes or 
latest edition of National Electrical Code 
ANSI/NFPA 70.
The water heater is completely wired to 
the junction box inside jacket at the top 
front of the water heater. An opening for 
1/2″ or 3/4″ electrical fitting is provided 
for field wiring connections.
The voltage requirements and wattage 
load for the water heater are specified  
on the rating plate on the front of the 
water heater. 
The branch circuit wiring should include either:
 Metallic conduit or metallic sheathed 
cable approved for use as a 
grounding conductor and installed 
with fittings approved for the 
purpose.
 Non-metallic sheathed cable, metallic 
conduit or metallic sheathed cable 
not approved for use as a ground 
conductor shall include a separate 
conductor for grounding. It should be 
attached to the ground terminals of 
the water heater and the electrical 
distribution box.
WARNING
WARNING
Water heater junction box.
Junction 
box cover
Wire connections
Ground screw
Conduit 
connector
   Total Water      Recommended Over Current Protection  Copper Wire Size AWG Based  
   Heater Wattage      (fuse or circuit breaker amperage rating)  on N.E.C. Table 310-16 (75°C)
     208V 240V 277V 480V  208V 240V 277V 480V
    3,000    20  20  –  15    12  12  –  14
    4,000    25  25  –  15    10  10  –  14
    4,500    30  25  –  15    10  10  –  14
    5,000    30  30  –  15    10  10  –  14
    5,500    35  30  –  15    8  10  –  14
    6,000    35  30  –  15    8  10  –  14
    8,000    45  40  –  20    8  8  –  12
    9,000    50  45  –  25    8  8  –  10
   10,000    –  50  –  25    –  8  –  10
   11,000    –  50  –  25    –  8  –  10
   12,000    –  –   –  30    –  –  –  10
Single Phase
Wiring
3 Phase
Wiring
!










