Which black wire on the back of the ej341 connects to the load? and the other one connects to the electric panel wire?

Load it the light, fan, motor, etc that consumes power
http://waterheatertimer.org/Electrical-terminology.html
http://waterheatertimer.org/Safe-electric-wiring.html

Typically, 120 volt incoming hot line is connected to black, white to neutral, ground to green...
Then load has 2 wires + ground ... the white connects to neutral, black connects to load wire, and ground to ground

Do not attempt to install this unless you capable and comfortable doing it,have correct tools and meters. you could receive a lethal shock, may start a fire. Call electrician. it will cheaper and less dangerous I had a trip to er for cut thumb, bill was around $2000.00 but I have excellent insurance and paid my $50.00

you need to look a instructions very carefully. your homes black wire goes to black wire. The copper will attach to switch mounting plate.
. the load side side is where attach the light or whatever the blue wire will attach to black wire fro load the white wire will attach to wire on load side.
Connect black and blue wires as shown in the diagram.
Cap the red wire
2. Depending upon line voltage, connect the mounting strap
green wire to either
(a) the timer green wire (for 120VAC) or
(b) the timer green/yellow wire (for 277VAC)
and the ground. Cap all unused wires.
3.Mount the timer inside electrical box using 2 mounting
screws provided.
4.Install cover plate.
5.Turn power on at the electrical panel

This thermostat is a DPST (Double Pole Single Throw) type meaning it will switch BOTH pairs of wires either ON or OFF. It is a type used primarily for 220 - 240 volt circuits and can switch up to 22 amps of load current. Most heaters will provide a wattage rating and some also provide a current rating as well. Since most electric heat circuits are connected to a 2 pole 15 or 20 amp circuit breaker (or fuses) via #12 copper wires it should work well. If connected to a circuit greater than 20 amps - as long as the heaters connected to the circuit do not draw more than 22 amps will also work fine.

If all is well so far, the continue. The thermostat should have 4 wires. Two of one color, two of another (black and red are common colors). One color group will be the LINE (powered) side, and the other group is the LOAD (heater) side. You should verify WHICH color group is which for best results. The switch will open and close a connection between the LINE wires and the LOAD wires.

The thermostat should be installed in an electrical switch box located on an interior wall at about 5 feet high and not above any heater or heat source. Do not locate it behind a door that swings open, etc. The box should be supplied by a circuit from the electrical panel that will connect to the LINE side color group wires *and* a circuit that will extend from the thermostat's LOAD color group wires to the heater's wire connections / terminals.

If running common #12/2 (for a 20 amp circuit breaker) or #14/2 (for a 15 amp circuit breaker) romex cable from the panel will have the Black and White wires connected to the thermostat's LINE wires and the Black and White wires in the #12/2 or #14/2 romex cable from the heater will be connected to the thermostat's LOAD wires. The ground wires will connect to each other AND a short length of the same size wire should be run from this same point to each: the ground terminal screw of the thermostat and (if using a metal electrical box) to the electrical switch box with a separately purchased green ground screw designed specifically for this purpose. Plastic boxes are not grounded.

Leave a comment if you have other questions & good luck!

I think you mean Ei343 instead of E1343.
I have manual for EJ341 and EJ343 that shows wiring for single-pole and 3-way.
I believe the EJ343 is wired same as Ei343 since Intermatic Load rating chart groups these timers together.
http://waterheatertimer.org/pdf/Intermatic-EJ343-timer.pdf

Load-rating chart:
http://waterheatertimer.org/pdf/Load-ratings-for-Intermatic.pdf
Load chart implies this is 120Volt in-wall timer for inductive and tungsten loads up to 400Watts.

Now here's something to remember.
When any timer is wired for 3-way, the timer replaces one of the 3-way switches.
The other 3-way switch remains, but the other 3-way switch has to be rewired differently so that 3-way timer works correctly.
When removing timer from 3-way circuit, don't forget to re-wire the remaining 3-way switch so it works correctly.

To convert your timer to operate single-pole: Timer Black wire connects to Hot wire from circuit breaker. Timer Blue wire connects to wire going to Light. Red wire is capped off.

To see similar wiring illustrations for newer generation Intermatic timer, open following link:
http://waterheatertimer.org/ST01C-program.html#ST01C

The following diagram is for timers with green, black, white, and red wires:
If your timer is different, add a comment with model number.




Manual says:
Timer-black-wire to Hot; Timer-red-wire to Load (lights)
Timer-white-wire to Neutral.
Here's what to do
1) Timer-green-wire connects to bare ground wire.
2) Switch has 2 wires. Take switch wires and connect them to timer-black-wire and timer-red-wire. Choose either one for now.
3) In back of electric box are white wires twisted together and covered with wire nut. Connect timer-white to these wires.
4) If electric box does not have white wires described above, then connect timer-white to bare ground.
5) Turn on electricity, and push manual override button. If lights come on, timer is wired correctly. If lights do not come on, then reverse timer-red and timer-black wires.

You posted under ST01C timer which has 3 wires: black blue and red (no white wire)
Your description seems to say your timer has 3 wires: black white and red

These are two different timers
I'm going to give you two different instructions that are dead-accurate for both types of timers above:

1) Instructions for ST01C and EJ500 Intermatic timers with black blue and red
Lets do the black and white with electricity:
The black Hot wire connects to Timer-black-wire
The white Neutral wire connects to white wire going to Load (to lights)

Now the black and white to the Load (lights)
The black to Load (to light) connects to Timer-blue-wire
The white wires are connected together with wire nut

The red wire is capped off, and used only if you have 3-way switching.
Green connects to bare ground

2) Instructions for all in-wall timers with black, red and white wires (except Aube series timers)
Lets do the black and white from electricity
The black Hot wire connects to Timer-black-wire
The white Neutral connects to Timer-white-wire and to white wire going to Load

Now the black and white to the Load
The black wire to Load connects to Timer-red-wire
all three white wires are connected and covered with wire nut
Green connects to bare ground

DO NOT CONNECT RED TO WHITE with any model in-wall timer and then turn on power or it can blow out the timer >>> I just did that while experimenting with the Utilitec 0192773.
Red wire goes to Load on all timers, except with Intermatic ST01C and EJ500

Switch has 2 wire > one of these wires is Hot and it connects to Timer black wire > the other wire goes to Load and connects to Timer red wire.

If you get these two wires reversed, timer will not run, so switch them. You know timer is running when dial on front of timer rotates with passing time. You can test for Hot wire by taking out switch, separate wires, turn on power, test each wire to bare ground, tester lights up with Hot wire.

Timer white wire goes Neutral. This wire is necessary to run clock inside timer. Locate Neutral wire inside box >> it is usually two or more white wires twisted together and pushed to back of box. If you do not have a Neutral wire, connect Timer white wire to bare ground wire ... until you can hire electrician to run additional wire to box.

GE 15086 is a 7-day programmable timer. It has more wires than spring-wound timer because clock motor runs on 120V circuit, just like ordinary electric clock. The clock on spring wound timer operated by a spring.



If I understand correctly, the old timer has 2 wires. One of these wires is the Hot wire ... and that wire will connect to GE timer black wire.
The other wire from old timer goes to Load ... and that wire will go to GE timer red wire.

Instructions on a lot of these timers say, it timer doesn't work, then reverse the two wires described above ... this is because timer only works when Timer black connects to Hot.

You can also turn on power and test each wire that came off old switch to bare ground wire. When tester lights up, that is Hot wire.

GE timer Green wire connects to bare ground wire.

Moving on to GE timer white wire. This wire is necessary for the clock to run. This wire connects to Neutral wire which is usually white. You can test for Neutral by testing Hot wire to each white wire in box ... when tester comes on, that is Neutral.

If you do not have a white Neutral wire, then connect GE timer white wire to bare ground wire. This is not code, but it will work fine until you hire electrician to run Neutral into box.

EJ341 has 2 wires

U need to open/unscrew back and look at bottom connections to the left ( looking from the back) Earth green and yellow- Blue is neutral and Brown is live you probably need electrical female spade connectors for your end of the 'hard' wire !!