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Convert 240 Volt to 120 Volt / with and without neutral wire

Resources:
Basic house wiring
Save electric wiring
Troubleshoot-household-electricity

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.

Buy:
1000 volt Tool kit
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
Buy
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
Lever switchWeatherproof lever switch on outdoor lights
Safely operate outdoor toggle switch
Replaces outdoor cover
Install over top of ordinary switch
Works with single-pole, double-pole, 3PST, 3-way, 4-way switches etc
Use weatherproof box for outdoor
Can be used indoor or outdoor

Buy:
Cantex lever switch
Leviton lever switch
Outdoor lever switches at Amazon

Resource
Cantex-toggle-switch-covers.pdf
Cantex-PVC-junction-boxes.pdf
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

Resource
How to select and install connectors

Multimeter
Test for breaks in wire/ Test for voltage
Most appliance require 80% rated voltage to function correctly
Buy
Analog multimeter
Multimeters at Amazon
Klein multimeter
Electric testers at Amazon
Clampmeter for testing amp flow on line
Resource:
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

Resource:
Basic house wiring
TerminalsWeatherproof outlet cover
Safely use extension cord with weather resistant cover

Buy:
Outlet covers
Weatherproof box
For adding outdoor wiring
Drill through back of indoor box, and through wall to install new outdoor outlet.

Buy
Hubbell Bell PVC box
Hubbell Bell aluminum box

Basic plan if you have Neutral connection:
Basic plan if you have Neutral connection:
Caution: When you work inside main breaker box ... even with main breaker OFF, the wires on the main breaker are HOT.

OK, so safety first.

240V breaker has 2 Hot wires that go to the 240V outlet or 240 volt water heater etc.

Take one of the 2 wires off the double breaker (preferably the white wire) and move that wire to the Neutral busbar.

After that the double breaker will supply 1 Hot wire and 1 Neutral wiregoing to outlet.
This will convert the outlet to 20 amp, 120Volt.

For receptacles or outlets, by code, you must also change the receptacle to standard 120V outlet, and if you're on a 20 amp breaker, it is code to use either 15 or 20 amp receptacle.
Convert 240 volt water heater to 120 volt ...
This works if the 240 volt circuit supplies power to only 1 Load, or the circuit is unused.

240 volt water heater circuitCautions and general instructions for changing 240 volt heater to 120 volt.
Big wires on main breaker are still Hot when main breaker is OFF.
When main breaker is OFF, then all small breakers are OFF and safe to work on.
Use only solid copper #12 and #10 wires ... if stranded wire is used, then connect stranded to short piece of solid copper and cover with twist on wire connector ... and put solid copper wire under screw plate on breaker and Neutral busbar. Always tighten screws and twist on connectors very tight.
Change wiring from 240 volt to 120 volt
Fig-1 shows typical 240V water heater circuit.


Two Hot wires connect to circuit breaker
Ground wire connects to Ground busbar

Fig-2 shows conversion to 120V:
Move black wire
 from 240V breaker to 120Volt circuit breaker rated for correct amps.
30 amp breakers and 10 gauge wire run cooler with less heat loss. Circuit is more efficient, and breaker box lasts longer ... so you can use a 20 amp single breaker, or a 30 amp single breaker because the orange wire is 10 gauge. If the wire is yellow, then wire is for 20 amp breaker only... do use 30 amp breaker and yellow 20 amp wire..

Move white wire from 240V breaker to Neutral busbar where ground wire connects. If White is not long enough, then buy short length of 10-2 or 12-12 sheathed cable, and take out length of white wire. Join white wires with twist on wire connector. Use only solid copper for #12 and #10 wires.

Modern breaker boxes have separate Neutral busbar where white wires are connected ... while illustration shows both Neutral and ground busbars on same side of box for purpose of illustration, the modern breaker box has Neutral and ground busbars on separate sides of box.
Always connect ground wire onto the ground busbar ... and white Neutral on the Neutral busbar. Water heater must be grounded for safety.
Resources:
Basic 240Volt water heater circuit
How to replace circuit breaker
How to install subpanel

Plan without Neutral connection:
buck boost transformer



Plan without Neutral connection:
Suppose you want to pull 120 V off a 240V circuit, but you still need the 240 volt to run water pump etc....

Then use Siemens industrial transformers
Typical household use would be to step 240 volt down to 120 volt.
Inexpensive .... reliable ... requires enclosure
Size: 5.1 x 5.6 x 3.6 inches ; 3 pounds
Different models have input for 120 with 24 volt AC output, input for 240 with 120 volt output ... or input 480 volt with 240 volt output.
Outputs are AC.

Buy:
Siemens industrial transformers

Choose enclosure that is large enough
Bud industries hinged box 6x8x4
Metal outdoor Enclosure/ with 1/2-3/4" knockouts
Polycarbonate enclosures drill for knockouts
Thomas and Betts 6x6x4 plastic with cover at Amazon
Bud industries 11x7x5 box no knockouts
Tapered drill bit 1/4"-1-3/8 holes
tapered drill bit
Example Nema 3R indoor outdoor enclosures
2T511GA enclosureAltelix enclosure

Resources:
Siemens control transformers
Siemens transformers
Siemens MT0050AExample wiring diagram for Siemens industrial transformer
If the input voltage is 220-230-240 volt, then connect one wire to terminals H1 and H3, connect other wire to H2 and H4.

If input voltage is 440-460-480 volt (480 for Americas), then connect one wire to H1 and other wire to H4, then jumper a wire between H2 and H3.
Larger image of transformer
Buy:
Siemens MT0050 industrial transformer

Note: 60 Hz Hot to Hot 240 volt is for power grid in Americas, 50 Hz Hot to Neutral 230 for Europe, and 50 Hz Hot to Neutral 220 for Australia etc.

When ordering: "If the dual voltage is separated by an “X” (120 x 240), the transformer can be connected only for 120 volts or 240 volts.
But, if it is separated by a “slash” (120/240), an additional Neutral connection is possible since the mid-point becomes available for 240/120 3-wire operation."
Resource pdf pg 4
Read more about transformers
Encapsulated step down Transformer will do same as Siemens transformer, except cost more since they come inside a metal enclosure/
Typical household use would be to step 240 volt down to 120 volt.
Convert 240Volt to 120Volt without neutral wire from breaker box

Convert 480Volt to 240Volt
Type 3R outdoor enclosure

 Wiring:
480Volt input connects to H1 H4, and then H2 and H3 are connected together
240Volt output connects to X1 X4, and then X2 and X3 are connected together

240Volt input connects to H1 H4, and then H3 connects to H1, and H2 connects to H4
120Volt output connects to X1 X4, and then X3 connects to X2
Buy:
500 watt 240-120 volt step down
1000 watt 240-120 volt step down
1000 watt step down
2000 watt 240 volt to 120 volt step down
Encapsulated transformers
Acme step down - 120/240 primary/ 120 240 secondary

Resources:
Acme ransformer wiring
Dry transformer installation
Match wire and breaker size
How to wire a subpanel
Read about household single-phase electricity
Read about 3-phase
How to wire 3-phase timers


Bring in a Neutral from nearby outlet
Bring in a Neutral from nearby outlet
Strategy for pool pump, shop tools, irrigation load etc
Bring neutral from nearby outlet or light fixture.
Note: 120 volt circuit needs Hot and Neutral, while 240 volt typically has 2 Hots and no Neutral. So the circuit needs a Neutral wire from a nearby 120 volt outlet ....

So why not just bring a Hot and Neutral over from the Nearby 120 volt outlet?
Answer: The motor load is 6 amps, but the 120 volt outlet is on a 15 amp breaker with safe maximum 80% = 12 amps. If the 15 amp circuit already supports several Loads, there is not enough spare amperage for the motor.
Note: Code says that Neutral wire is never switched on-off ... only the Hot wire is switched.
Buy:
Motor switch
MS302 30 amp 2-pole switch
MS402 40 amp 2-pole switch
ANL fuseholder
Buy fuseholders
Fuse blocks at Amazon
Electrical terminals
Din rail fuseholder
10 x 38 mm fuse

Different gauge wires
in line fuse
Larger image
Get 120 volt from 240 volt line
Use in-line fuse when connecting 2 different gauge wires

Illustration shows how to pull 120V from 240Volt line.
Only possible by code if 240Volt line has neutral wire.
Connect smaller 12 gauge wire to 10 gauge wire using twist on wire connector.
All connections must be inside electrically rated enclosed box with cover.

10 gauge wire is protected by 30 amp breaker
The amp draw on 30 amp breaker is too large for 12 gauge wire.
12 gauge wire should have 20 amp breaker.
Use fuseholder with 20 amp fuse.
Fuse will protect entire length of 12 gauge wire.
Connect fuse to Hot wire.
Not necessary to put fuse on Neutral
If the 12 gauge wire was wired for 240V, then fuses can be added to both hot wires.
Always make connections inside a box with cover
Buy:
ANL fuseholder
Buy fuseholders
Resource
See wire sizes
surface mount fuseholder Surface mount ANL fuseholder
Buy:
ANL fuseholder
e2 fuseholder with platinum plating
ANL fuses

Din rail fuseholder
Install fuse in-line so circuit can be turned on.
Multiple fuses and breakers on same circuit are fine.
Buy:
Din rail fuseholder
10 x 38 mm fuse

Mersen DC fuseholder
Mersen DC fuseholders
Photovoltaic fuse
20 amp DC fuse

14 x 51mm fuseholder and fuse

Din rails

Din rail mounted circuit breakers
step up transformer

Step up -or- step down transformer

Convert 120 volt into 240 volt/ or 240 into 120 Volt

Buy:
500 watt transformer
1500 watt transformer
3000 watt transformer

Resource;
Step / step down transformer basics
Transformer basics .pdf

240 Volt subpanel Resource
Change 240 Volt subpanel to 120 Volt
water heater circuitLarger image
Toggle between under counter water heater and dishwasher

Same wiring for either 120 or 240 volt loads
Code permits 15 or 20 amp switch on a 20 amp breaker ... as long as switch is rated for same voltage and more amps than Load (anything that consumes power is Load)

Objective 1: Either the dishwasher has power or the under-counter water heater has power. But neither at same time. Why? Because safe maximum amps on 20 amp breaker is 80% or 16 amps ... while dishwasher and water heater together consume 23 amps.
Do not install 30 amp circuit breaker unless wire is also increased in size from 12 ga to 10 gauge. Color code for wire

How to wire: Incoming wire from breaker has 2 wires. If voltage is 120, then the white Neutral wire is never switched on-off. Connect white Neutral wire to each appliance.
Black Hot wire is switched on-off. Connect Hot wire to COM terminal on the 3-way switch (dark or different color screw). Then run a Hot wire to each appliance from the other two screws on switched.



Heavier amp loads, or more voltage, such as 30 amp 240 volt water heater, use a 30 amp 3-way switch (safe max 23 amps).
Other options, for higher amperage loads and motor loads (such as irrigation pumps, shop tools etc), include using a switch (or timer) to toggle loads with 30-40 amp open frame relay.
Buy 30 amp 3-way:
Leviton 3033 switch 
30 amp 3-way switch
Dishwashers 
Resource:
How to wire open frame relay




Buy
Tools
Milwaukee
DEWALT
Black and Decker
Stanley
SKIL
Makita
Porter-Cable
Bosch

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

Campbell Hausfeld air powered
Tekton automotive

Powerbuilt automotive
Saws and saw blades

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