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Timer caught fire/
Fire inside timer/ Overheating


Test for breaks in wire/ Test for voltage
Most appliance require 80% rated voltage to function correctly
Multimeters at Amazon
Electric testers at Amazon
How to test and replace element
How to test thermocouple
Element tests for 120 volts
How to test wire
Safety when testing wires:
Never touch wet or previously flooded appliance.
Never stand on wet surface when working on electric.
Never stand on bare soil, put down dry boards.
Tape tester leads to wood sticks to keep hands away from power.
Use non-contact voltage tester before touching wires.
Never touch or lean into any made of metal.
Remove metal objects from pockets.
Do not use oxygen or fuel accelerants in same room as electrical repairs

Basic house wiring

Non-contact voltage tester

Test for power without touching connectors
NEVER assume power is OFF
Non-contact voltage tester Amazon
Electric testers at Amazon
How to test electric power is off
wire connector assortment

Twist-on wire connector assortments

Do not reuse old connectors
Connector assortment at Amazon
Connector assortment at Amazon
How to select and install twist-on wire connectors
Weatherproof wire connector

Weatherproof wire connector

Connector cavity is full of silicone
Built-in cover keeps silicone in place
Protect from water, dust etc
Buy from my affiliate links
Weatherproof size 14 to 6 Amazon
Weatherproof size 22 to 8 Amazon

How to select and install connectors
Wire connector wrench
Wrench to apply wire connectors
Tighten connector

Wire connector blaster
Twist connector wrenches at Amazon

How to twist wire
How to select and install twist-on wire connectors

Blue for 16-14 wire
Yellow for 12-10 wire

How to install terminals


Terminal kit
Blue for 16-14 wire
Yellow for 12-10 wire
Push on wire connectors

Push-on wire connectors in place of twist-on connectors

Push on wire connectors Amazon
Red 3P connector for 10-14 gauge wire
Lever connectors for stranded wire at Amazon
remove cable staple
End cutting nippers at Amazon

linesman pliers
When removing insulation from wire, do NOT score or put cuts on surface of copper wire. Doing so increases resistances on wire and creates weak point.
Buy tools:
Wire strippers at Amazon
Linesman pliers
Utility knife at Amazon
End cutting nippers at Amazon

Keep wires straight
Use solid copper wire
If wiring terminal or end of wire are covered with green, use emery board to clean terminal and sandpaper to clean wire.
timer fire Timer fire:
Cause: Stranded wire under COM2 terminal got hot, came loose and caused fire
Replace timer
When installing timer, Use only solid copper wire
Solder end of stranded wire to make solid

Resources: for timer manuals, wiring and purchase
GM40 series, GE 15000 series, Tork series
Intermatic defrost timers

Match breaker and wire size

Fire inside timer caused by stranded wire
Keep enclosure door closed at all times

Two alternatives.
1. crimp a ferrule onto the wire so the screw terminal digs into that, and the strands are protected.
2. Use a terminal type in which the wire strands are protected from the screw.

Fire caused by stranded wire
Do not use stranded wire under screw plate on timer, contactor, relay, outlet, switch or any electrical device

What is amperage
Basic house wiring
How to troubleshoot household electricity
Causes of timer fire
Insdulation under screw plate
Larger image
Both wires MUST be same gauge
Straighten each wire
If wire is corroded or overheated, clean the end with sandpaper and wipe with cloth.
If wire has been melted, cut back and reattach, or replace wire.
Tighten screw very tight against copper wire

Use wire connector  
Push on wire connectors
Use push-on wire connectors
3 wires/ or different gauge wires
Join wires with wire connector or push-on connector
Run jumper to screw terminal.
Push on wire connectors at Amazon
Red 3P connector (shown) for 10-14 gauge wire
Connector assortment
How to select and install wire connector

Larger image
Fire safety/ Do not put stranded wire under screw plate
Do not install stranded wire under screw.
Problem1: picture shows 2 different gauge wires under screw plate
Problem2: Stranded wire will expand and contract and come loose under screw plate, even if it is the only wire under the screw plate
Attach stranded wire and solid wire with wire connector, and run solid copper jumper wire to screw terminal
Take photo of wires before starting.

Timer caught fire
Load ratings for Intermatic timers/ pdf
10-3-wire  12 Ga
10 gauge or 12 gauge?
Compare your wire with short pieces of 10 and 12 gauge wire from local box store

10 gauge for 30 amp breaker.
10 gauge wire can have black-white and sometimes black-red

12 gauge for 20 amp breaker
12 gauge will have black and white wires
Match color code and amp rating for wire
Basic house wiring
Add black tape when White wire carries voltage (applies to 208 and 240V circuits)
With 120 and 277 Volt circuits, White wire is Neutral, and Black is Hot
With 208 and 240 circuits, both wires are Hot, and both wires carry voltage
Black tape on White wire identifies wire is Hot and not Neutral
Prevent fire
Install arc fault breaker Arc fault breaker can prevent fire inside timer caused by a loose wire or stranded wire
Arc fault breaker trips when there is short to ground (same as GFCI) but it also trips when a spark is detected on the line
Spark from loose wire will trip breaker... this will signal that wire is loose under the screw plate, or there is a ground fault on the line
Only one GFCI-protection device per circuit... so you cannot have GFCI and Arc fault on same circuit... nor can you have 2 GFCIs on same circuit.... they will cause tripping
It is OK to have more than one ordinary breaker or fuse per circuit

Arc fault breakers at Amazon

How to wire arc fault
How to wire GFCI
prevent timer fire Keep enclosure door closed
All electical connections must be made inside a box, and each box must have cover or dor to stop fire from spreading
High heat even will be confined inside the box, and provide fire safety

All electrical devices have amp rating and max amp overload rating

Why you need ground wire
Fire inside Intermatic timer Match wire and breaker size with load
Match timer rating with load
Attach wires to enclosure
Attach wires to structure

Color code for wire and breaker
Intermatic enclosures
Romex connector Use Wire connectors, or conduit clamps to secure wire to enclosure
By code, all wire must be securely attached to enclosure to prevent wire pull-out.
Wires or conduit must be secured to structure, so there are no loose wires.
Wires inside the enclosure cannot lay over top of connection terminals.
Join all ground wires together and cover with wire connector.
Push ground wires down and away from connection terminals.

Wire clamps
Outlet is warm   circuit breakers are warm General household check-up
Feel if breakers are warm-hot
Check outlets, switches and other electrical devices for heat
Use nose to smell for burned parts
Use ears to hear cracklings
Use eyes and look for sparks
How to troubleshoot household electricity
burned resistor on timer
This timer appears to have damage on 1 component... but actually several components have dark solder connections, showing that several parts overheated
Burned resistor on timer
R1 resistor burned, R2 resistor burned
Replace timer
No prevention steps
Check that timer is receiving correct voltage and Load does not exceed rating.

This is common problem as timer ages
Normally if R1 or R2 are burned... look carefully and other nearby parts have signs of burning also.
R1-R2 are usually first place you see overheat problem
This is true with older and newer models in the GM and Woods and Tork series digital timers, including defrost series

Frequently these timers with burned R1 are sold on ebay after they have been removed from service... simply because the timer looks good or repair seems simple.

Check if one of the relays is still functional.. sometimes a timer can be used with one relay.

Related solutions:
Use correct voltage to match timer
Do not exceed load rating on timer
Use correct wire and breaker

Match breaker and wire size
Figure volts amps watts

More resources:
Compare similar timers
Compare all box timers
GM series defrost timers
R1 resistor Unburned R1 R2 resistors
Note there are no high-heat or burn residue at end of each part
R1 resistor Unburned R1 R2 resistors
Note there is no high-heat or burn residue at end of each part
burned timer

Relay points
Points on timer relay can get burned
It is normal for carbon to build up on points, causing loss of electrical contact.
Turn power off, and use nail file to clean points

There are no replacement relays for these timers... but you can clean points with a nail file... and if relay is bad, frequently one of the two relays will still function, and load can be controlled by turning off 1 hot wire

How to wire GM40 timer
Difference between relay and contactor
Burned part on electric water heater
Replace part, cut back burned wire
Electric water heater parts and replacement

Contactors/ relays
Install and troubleshoot garbage disposal Waste King disposal
Programmable timers

Woods timers
surge protection
Industrial electric

Industrial supplies

Tools and home improvement

Home and garden

Hayward pool
Pentair pool

Southwire electric

Black and Decker

Irwin Hand tools
Klein hand tools
Fluke electrical testing
Dremel hobby tools

Campbell Hausfeld air powered
Tekton automotive

Powerbuilt automotive
Saws and saw blades
box timers Resource:
Compare box timers
DPDT timers
Control water heater w/ Z-wave
Intermatic control centers Resource:
Intermatic control centers: and parts
Digital control centers and parts
Tork control centers and parts
All control centers and parts
programmable timer Resource:
Programmable timers
Countdown timers
Off delay timers
On delay timers
Timer modules
Din rail
Twin & one-shot
Low voltage power packs Recirculation systems
Enter Amazon from my links

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