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  What Size Wire Do I Need? How Do I Know What Circuit I Have?



 

Product Code: WIRES-AND-CIRCUIT-BREAKERS
 

Description
 
How many amps does my unit draw?  What size wire should I use?

Here are some basic tips to help you determine what you need.


Wire Guide :


Maximum Amps
Gauge


7
18


10
16


15
14


20
12


30
10


40
8


55
6

Go to the next larger wire size if your run is more than 100 feet, inside a conduit, or ganged with other wires where the heat dissipation may be inhibited.


After the gauge number, there will be a number signifying the amount of service wires in the cable.  The picture above shows 2 service wires plus a ground.  If this wire was 14 gauge, it would be labeled "14-2".  (The ground wire does not count.)

In the example above, if this wire was 12 gauge it would be labeled "12-3".  This wire has 3 service wires plus a ground.

Circuit Breakers:

When updating an appliance or air conditioner, it is important to determine the correct current draw.  If your circuit breaker is 20 amps you cannot install a product that requires 30 amps.  It is not as simple as just changing the circuit breaker.  The wiring to the appliance also needs to be changed.  Although, when the opposite occurs, the solution is easier.  If you are going from an appliance that required 30 amps and your new appliance requires only 20 amps, the wire does not need to be changed.  The circuit breaker and the outlet receptacle will need to be changed.

Below are examples of typical circuit breakers.  The one on the left is an example of a 110 volt 30 amp breaker.  The 30 on the switch indicates that it is 30 amps.  The one on the right is an example of a 220 volt 20 amp breaker.  Once again, the 20 on the switch indicates the amperage.  These are only examples and your breakers may be different.  If you are not sure consult with your electrician before ordering.



This information is only a guide.  If you have questions please call us or consult with your electrician.

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