A properly sized disconnect switch for a single motor will:

  1. Have an ampere rating greater than or equal to 115 percent of the rated motor full load current; or,
  2. Have a HP rating greater than or equal to the rated motor HP (at applied voltage) if the disconnect switch under consideration is HP rated.

What size disconnect do I need?

Now, since they come in staged sizes, the disconnect amperage must be higher than the amperage of your circuit. For example, if you have a 20-amp circuit, you need a 30-amp disconnect. If you have a 40, you need a 60, etc.

What size disconnect switch do I need?





Let’s take a high-level look. When you install a disconnect switch for a single-motor application, it must meet the following two criteria: Have an ampere rating at least 115% of the rated motor full load current. Have a horsepower rating the same or greater as the rated motor horsepower (at applied voltage)

What is minimum circuit disconnect?

The provisions of NEC 440.12(A)(1) generally require the ampere rating of the disconnecting means must also be at least 115% of the sum of all currents at rated-load condition. This minimum rating would then be 115% x 19.2 amperes = 22.3 amperes.

What is code for electrical disconnects?

The 2020 NEC requires an exterior emergency disconnect for one- and two-family dwelling units.

Can a breaker be used as a disconnect?

A circuit breaker, on the other hand, can be used to protect a circuit that contains many switches or devices. An exception to this is a disconnect switch, which is used to connect or disconnect power to an entire control panel, or machine.

What size fuses for 200 amp disconnect?





200 AMP, 2-Pole, General Duty Safety Switch, Cartridge Fuse Type, Fusible with Neutral, 240 VAC, NEMA 1. Uses: FLNR Series Fuses. Enclosure Dims: H: 25.25″, W: 16.00″, D: 6.14″. Non-Fused Disconnect Switch.

How do I choose a disconnect switch?

Select a disconnect switch with the same or greater horsepower rating as the appliance. The disconnect switch must also have the correct fuse size. An appliance requiring a 30-amp double circuit breaker will need a disconnect rated to its horsepower and will accept two 30-amp fuses.

How do you size a DC disconnect?

In general, in order to size an AC or DC disconnect you must consider the voltage, circuit load, amps or breaker size and wiring of your equipment, components and connectivity throughout your solar array.

Which of the following are standard size circuit breakers?

Standard sizes for fuses and fixed trip circuit breakers, per 240.6, are 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000 5000, and 6000 amps.

What is the 6 disconnect rule?



The rule is six disconnecting means for each service, not six service disconnecting means per building. If the building has two services, you can have a total of 12 service disconnects (six disconnects per service).

What is the 6 breaker rule?

The “six breaker throw rule” was a requirement in the National Electrical Code that a service must have have a main disconnect that shuts off all power and it cannot take more than six switch throws to do it, and the main disconnect(s) also must be clearly marked, as in the photo above.

How high can you mount A disconnect?

6 ft 7 in



The NEC does not mandate a minimum mounting height for panelboards, disconnects, or meter enclosures. But switches, and circuit breakers used as switches, shall be installed so the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, is not more than 6 ft 7 in.

How far can a disconnect be from a condenser?

Definition of readily accessible & within sight

This distance is typically described as within 50 feet (15 meters), and in practice at most residential properties the disconnect is much closer (3-6 ft), on a wall or standard near the compressor/condenser unit.

What is maximum mounting height for electrical panel?

A height limit applies to mounting a panel box. The circuit breaker at the top of the box may not be higher than 6-foot 7-inches from the floor. A permanent platform must be below the panel box if the top circuit breaker exceeds this specific height. No defining height is mandated from floor to panel box base.

What is code for AC disconnect?



The 2008 National Electric Code requires: 440.14 Location. Disconnecting means shall be located within sight from and readily accessible from the air-conditioning or refrigerating equipment. The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigerating equipment.

How high should a disconnect be from the ground?

All switches and circuit breakers must be installed so the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, isn’t more than 6 feet 7 inches above the floor or working platform.

Can a breaker be used as a disconnect for AC unit?

There has to be a service disconnect in line sight of the unit. A breaker/fuse box outside by the unit would be considered compliant as well but if the breaker/fuse box is inside or on the other side of the house ect a service disconnect should be installed. Had an install done.

Do you need fused disconnect for AC?

Nameplate on the HVAC unit should tell you the maximum fuse/circuit breaker size required. If your breaker matches that then you’re fine, no fuses necessary. On the other hand, a fused disconnect is an extra bit of redundancy. Especially helpful if the breaker size specified on the HVAC unit is an oddball.

Can I use a 60 amp disconnect on a 30 amp breaker?



As long as the circuit is on the proper size breaker, there’s nothing wrong with using a 60 AmpDisconnect on a 30 Amp unit.

What size breaker do I need for AC disconnect?

If you go smaller then 20 amp, you will experience nuisance tripping, and you are not allowed to go larger than 25 amps. If you have the circuit breaker at the panel, you could use a non-fused disconnect. Most of them are rated at 30 or 60 amps, which is more than what you need, and would be fine.