How many amps can be loaded on a 120V 20amp circuit?

Answer 1

The determining factor is that the maximum unbalanced neutral current must not exceed 20 amperes. If all circuits are on the same phase, or hot leg, you would be limited to one. That's because two 20A circuits on the same phase would cause 40A of neutral current to flow. Very bad... If you have a 240 volt Edison type service with two hot legs (typical in US homes), and you use one circuit from each hot leg, you are allowed two. If you load one or the other circuit to 20A, the maximum neutral current would be 20A. If you load both circuits to 20A at the same time, the neutral current falls to zero because the two legs balance each other out. No matter how you load the two circuits (as long as each does not exceed 20A), the neutral current will never exceed 20A. If you have three-phase power, then you are allowed three circuits, as long as they are one from each phase, for the same reason as above. Of course, all this is technically accurate, and will work, but you must also check your local electrical code, because most have some specific rules and exceptions to the above. Be legal, be safe! IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS. If you do this work yourself, always turn off the power at the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicator

to insure the circuit is, in fact, de-energized.

Answer 2

In theory, 20 amps at unity power factor (pure resistive load, no motors or Transformers), although it is good practice to not load circuits to 100% capacity. Also consider that many loads draw more current for transients than in normal operation--for example an incandescent lamp will pull a lot more current when first turned on and when the filament breaks.

Answer 3

For 120V (normal in the U.S.) it would be 20x120 = 2,400; *but* this puts the circuit breaker on the edge of trip. Normally, you would want to use 16A or less (NEC rule)

which would make 1,920 the practical long-term maximum.

Answer 4

In the United States, commercial and industrial installations are limited to 13 receptacles on a 20 amp circuit, 10 receptacles on a 15 amp circuit.

There is no limit for residential installations.

Answer 5

A 20 amp breaker is designed to trip when it detects a current over 20 amps. Now it takes a small but finite time to recognize this excess current and trip. So given the duration of the over current spike it could be over 20 amps for a small fraction of a second before tripping. However, given that a very sharp spike could exceed 20 amps, there is also a limit for a continuous load and this is 80% of the rated amount. In this case 16 amps continuous.

Answer 6

It does not matter whether the wire is stranded or solid a #12 conductor is rated at 20 amps. Stranded wire is usually used in conduit systems as the wire is easier to pull around bends in the conduit as compared to solid wire.

Answer 7

Just one 20 amp circuit per neutral on 12 AWG wire. There may be multiple devices on the circuit, but end-to-end it is just a single neutral.