Why can you only put 13 receptacles on a 20 amp circuit breaker in commercial building?

Answer 1

Because the National Electric Code (NEC) requires that you count every duplex outlet as 1.5 amps of load. (See section 220-3.c.6). 13 outlets x 1.5 amps per outlet = 19.5 amps.

You can only have ten duplex outlets on a 15 amp circuit breaker.

Note that these requirements are only for commerical applications and do not apply for residential applications. In many cases the electricians try and apply the same rules to sell larger switches to homeowners.

If that wasn't bad enough, you must also install outlets every 12 feet per section 210-52.a. In the kitchen you must put the outlets for every two feet of countertop.

Answer 2

When designing or installing receptacles on a 20 circuit, each receptacle must be consider to draw some load. I think the code rates each receptacle at 180 volt-amps. For a 20 circuit 20 amps * 120 volts = 2400 watts

You should not exceed the 2400 watts, and meet the code.
13 rec * 180 volt-amps = 2340 watts. This is as high at you can go. Actually, I think 13 is to many, most engineers only load a circuit to 80%, again this is in the National Electrical Code. Following the code, 2400 * .8 = 1920 dividing by 180
gives you 10.66. You should only put 10 receptacles on a circuit. I think an electrical inspector would tell you this also.

Answer 3

Each receptacle can draw power through the breaker switch. If there are two many receptacle on one line for any certain breaker swith the load will be too much for it to handle and you'll have problems, i.e, fire. The ohter reason why that is in your area is based on what the greater powers want. Really if they say you can have more or less then that is why.

Answer 4

As long as the circuit has the correct size wire and the correct size breaker to protect the wire there is not a safety issue. The more outlets you have on a circuit however the greater the chance that too many electrical devices will be used and the breaker will trip. This is a nuisance for everyone. It is reasonable for electric codes to address this issue.

Answer 5

It limits the total current draw to some extent and it's probably the electrical code for your area.....