GM40 timer
Keep wires and conduit straight
How to wire EH40 / 240 volt water heater timer/

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Use only 600 volt wire.
Lamp cord, extension cords are not rated 600 volt.
Use copper wire only. Aluminum wire is fire risk and should be avoided or installed by professional.

30 amp breaker use 10 gauge /
120-240 volt 30 amp outlet can be installed on 30 amp breaker only/ use 10 gauge wire ... cannot be connected to 15-20-40 amp breaker.

Orange/ #10 gauge wire, with ground ... 30 amp capacity. Safe maximum: 30 x 80% = 24 amps.
Buy:
10-2 gauge/ 30 amp
10-3/ 30 amp
Southwire electric tools
Yellow 12 gauge 20 amp
120 volt 20 amp outlet can be installed on 20 amp breaker, but not 15 amp breaker/ use 12 ga wire.
... cannot be connected to 30-40 amp breaker. 1

Yellow/ #12 gauge wire, with ground ... 20 amp capacity. Safe maximum 16 amps.
Buy:
12-2 gauge/ 20 amp
12-3/ 20 amp

NMB is house wiring
UF is underground
Rolls of stranded wire
HOOK UP Wires
multimeter
Multimeters
Voltage is tested across two separate wires. Ohms or resistance is tested across both ends of same wire. Amperage is tested along one or two points on same wire.
Buy:
Analog multimeter
Multimeters at Amazon
Klein multimeter
Electric testers at Amazon
Clampmeter for testing amp flow on line
Southwire armored cable cutter
Electrical tools must be insulated.
Always best to disconnect power, but insulation failure, lack of proper grounding, grounded neutral, lack of GFCI, out-of-code wiring, generator operating without transfer switch, and other problems still pose a risk to anyone working on electric power ... even when breaker is off.

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Electrician tools kits
KLEIN TOOLS
Tools kits
IRWIN tools
KNIPEX

Telephone cable knife
Low Voltage Mounting Bracket for Telephone

Protect wiring from damage
Use nipper instead of pliers or screwdriver for removing staples (and nails). Do not damage cable or wires inside cable.

-Code says: Cable SHALL BE secured without damage to the outer covering. NEC sec. 336-15
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End cutting nippers at Amazon


Electrically insulated tools
When removing insulation from wire, do NOT score or put cuts on surface of copper wire. Doing so increases resistance and heat on wire and creates possible weak point.
Buy tools:
KLEIN TOOLS
Wire strippers at Amazon
Electric Wire Stripping Machine
Linesman pliers
Utility knife at Amazon

EH40
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EH40 240Volt timer
30 Amp programmable/ DPST
Minimum 1 minute set times
Up to 6 on-off per week
AA battery for backup and power-outage carryover
1 year limited warranty
Override button located on face of timer.
Temperature range -40ºF to 104ºF/ back-up battery will fail when exposed to freezing temperatures
7-3/4" high x 3" deep x 5" wide
Use 10 gauge wire, 30 amp breaker rated for 4500+ watt element

Inductive: 30 Amp, 240 VAC
Resistive: 30 Amp, 240 VAC
Tungsten: 5 Amp, 240 VAC
1 ½ HP, 240 VAC
Reset timer using reset button before programming
EH40
Larger image of wiring
Different arrangement of wires


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EH40 water heater timer
Wiring can vary because both wires are HOT: Jumpers can connect 2-3 -or- 2-5 etc. Different arrangement of wires
Terminals 3-4 and 5-6 are simple on-off relay switches that activate when timer turns on-off.  Terminals 1 and 2 are for powering the timer and relay switches. Relay switch terminals 3-4 and 5-6 are 'dry' and receive no voltage when power is connected to terminals 1 and 2... relay switch terminals are connected to terminals 1 and 2 as illustrated.
Always connect ground wires together on the green ground screw.
If wires are too short, but short length of wire and connect wires using wire connector.
Attach wire or conduit to enclosure using clamp

Buy:
EH40     240Volt 7-day digital timer
30 amp timers
10-2 wire<

Resources:
EH40 sell sheet
EH40 manual
Figure volts amps watt for water heater
Basic water heater circuit
Color code wire
Compare all box type water heater timers
Compare 16 ways to control water heater


Jumper wire connects two terminals
10 gauge wire, 30 amp breaker
Timer rated 30 amp, 4500+ watt water heater
EH40 does not have a connection terminal for Neutral.

Keep end of wires straight.
Clean wire ends with sandpaper if discolored
Tighten screws very tight
Neutral wire?
Does 240 volt circuit have a Neutral? Generally no, because both wires are Hot. But some 240 volt circuits have 12-3 wire with 2 Hots and a Neutral wire.
If circuit has Neutral, then do not attach to screw terminal. Instead attach both Neutrals together with a wire connector inside the EH40 wiring compartment.
Resources:
See wiring for main breaker box
Basic water heater circuit
      Attach wire or conduit to enclosure using clamp
Keep enclosure door closed
Keep plastic cover over wiring terminals unless power is OFF
Use correct wire and breaker
Buy:
10-2 wire
Southwire electrical tools and wire
Multimeter
Electrical testers

Resources:

 Select wire and breaker size                       
Read about Wire connector
EH40 controls 2 water heaters EH40 controls 2 water heaters/ same schedule
Must use 2 separate 30 amp breakers

Buy:
EH40     240Volt 7-day digital timer

Resources:
2 water heaters
Repair EH40?
Resources:
How to repair EH40 timer
Use 24 hour mechanical  timer
Use ET series timer
eh40 controls 2 water heaters

EH40 controls 2 water heaters/ different schedules
Override button located on face of timer

Buy:
EH40     240Volt 7-day digital timer

Resources:>
2 water heaters
EH40 controls 120 volt load
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EH40 controls 120 volt load
Use to power power-indicator light, pump, or any 120 volt load with same schedule as water heater

Buy:

EH40     240Volt 7-day digital timer
Indicator lights
High grade indicator

Resources:
Water heater recirculation system
EH40 off-peak water heater
Larger image off-peak wiring
EH40 off-peak water heater
Use off peak strategy in conjunction with timer: Top of tank is heated while lower part  of tank is off. Lets you use timer to produce some hot water during peak prices, without turning water heater completely off.
\
Buy:
EH40     240Volt 7-day digital timer

Resources:
How to wire off-peak water heater
How to wire water heater thermostats

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Fire safety/ Do not use stranded wire under screw plate
Stranded wire can come loose under screw plate, causing connection to heat up, and become fire hazard over time.
Keep enclosure door closed.
Attach stranded wire and solid wire with wire connector, and run solid copper jumper wire to screw terminal
No insulation under screw plate
Use only solid copper wire
Do not put insulation under screw terminal
Take photo of wires before starting
Insdulation under screw plate
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Maximum 2 solid copper wires under screw plate
Max 2 wires under screw plate
Each wire must be same gauge
Attach multiple wires with wire connector, and run jumper to screw terminal
Resources:
Wire and breaker size charts
EH40 is battery operated timer
Battery compartment located beneath buttons
Size AA battery lasts 2-3 years

Buy:
Batteries

Resources:
How to repair EH40 timer
EH40 in exterior enclosureEH40 can be installed inside a PLASTIC OR METAL OUTDOOR ENCLOSURE
Be mindful that EH40 is battery operated.
Batteries grow weak much faster in cold temperatures (for example car battery ... which is rated for cold)
The AA battery is not rated for continual exposure to very cold temperatures.
However, unlike the standard Nema1 indoor inclosure that comes with EH40, a Nema 3R outdoor enclosure can protect against dust and dirt accumulation, in addition to outdoor rain.
Buy:
Nema 3R metal enclosure 2T2485GA
Nema 3R plastic enclosure 2T2485GA
Resources:
Boxes and enclosures
Code for installing electric boxes

Other choices can include the 30 amp  ET1700 series
Buy:
ET1705C/            Steel indoor box/ 30 amp/ 7-day/ SPST programmable/ at Amazon
ET1705CPD82/   Plastic outdoor box w/ see-thru door/ 30 amp
ET1705CR/          Steel outdoor box/ 30 amp
Resource:
ET series timers and manuals
WH40
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WH40 water heater timer
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Optional 240 volt timer: WH40
Timer rated 40 amp.; 240 volt, commercial quality
24 hour mechanical timer
10,000 watt capacity> can control one or two water heaters
WH40 timer is same as T104 and T104-20, except WH40 has external override lever
Up to 12 on-off operations per day
Manual override reverses current program until next tripper returns timer to regular schedule
Buy:
WH40      208-240-277Volt 10000 watt 40 amp
T104-20 (WH40)     208-240-277V (no external switch)
156T1978 trippers
Replacement trippers
Clock motor WG1573
10-2 wire
Resources:
Wiring diagrams: How to wire WH40
WH40 manual
WH40 sell sheet
How to operate and set timer
List of replacement parts
color-code household wire Applies to 120 or 240 volt circuits
Inductive loads like motors and pumps might require larger size to meet start amps
Resistive loads like water heater and incandescent light bulbs do not consume more amperage at start up.
Resources:
Choose correct wire and breaker
Wire connectors
How to twist wire
Wire connectors
Basic house wiring

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Tools

DEWALT
Black and Decker
Stanley
SKIL
Makita
Porter-Cable
Bosch

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Fluke electrical testing
Dremel hobby tools

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