Choosing the Right Circuit Breaker
- Apr 12, 2017
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When adding or replacing a circuit breaker, picking the right unit is essential for safety and functionality.
Installing an incorrect breaker could result in little or no function, or even create an electrical or fire hazard.
Consider the following factors and choose the right breaker every time.
Determine the Circuit Breaker Type
First, you need to determine whether you need a standard breaker, a Ground Fault Circuit Interrupter (GFCI), or an Arc Fault Circuit Interrupter (AFCI).
If you’re replacing an old circuit breaker, you can tell the type by the presence of a “test” button alongside the usual on/off switch. If you’re adding a new circuit, consider its function: any area around water such as a bathroom or kitchen should be protected by a GFCI.
Identify the Manufacturer and Brand of the Breaker and Panel
The panel label will list acceptable breakers, and if not (or if it’s too worn to read), check the other breakers or call in an expert. Older Westinghouse circuit breakers are quite different from modern Siemens circuit breakers, for example.
Check the Electrical Specifications
Next, you will need to find out a range of specs. If you are replacing an old breaker, you’ll find all the info you need on the unit itself. Necessary information includes:
- Load and Trip Current
- Number of Poles
When you’re trying to determine amperage, but you do not have an old circuit breaker for comparison, you can use the wire gauge to guide your decision. You’ll find the gauge printed on the wire that will connect to the new breaker. The lower the gauge, the higher the breaker amperage. For example, a 10-gauge wire will need a 30-amp breaker, while a 14-gauge wire requires a 15-amp unit.
If adding a new circuit, always account for 125% of the circuit’s current when choosing an amperage rating. This ensures the safety of the system and is required by the US. National Electrical Code.
Check the Physical Specifications
Aside from electrical characteristics, you will also need to know specific physical requirements of the breaker:
- Connection (Bolt-On, Plug-In, etc.)
- Mounting (DIN Rail or Panel Mount)
- Frame Type
Confirm Any Special Requirements
For developers or contractors, you may need to fulfill certain special requirements for specific codes, localities, or client preferences. For example, you may need to use only new circuit breakers as opposed to reconditioned circuit breakers, you may need high vibration specifications for industrial facilities, or you may need to choose between a manual or automatic reset.
Temperature is also an important consideration, particularly for industrial systems. In temperatures above 104° F, standard circuit breakers require recalibration. Very high altitudes and very moist climates may also require derating.
If at any time during the circuit breaker selection process you are unsure or unsafe, stop what you’re doing. If you’re not completely confident the power is off, you’re guessing at voltage, or if you’re unclear if an appliance will require a one or two-pole breaker, put down the tools and call the experts.
Some cases are tougher than others to crack—an old, worn breaker may have faded labels, or a panel might look confusing. In these cases, it’s always a good idea to call the pros.
At Circuit Breaker Wholesale, we’ll match you with the right part, guaranteed. Call us up, send a photo of the breaker or panel, or even give us a description of the unit, and we will help you find the part you need.