Table 210.21(B)(2) Maximum Cord-and-Plug-Connected Load to Receptacle
Circuit Rating (Amperes) Receptacle Rating (Amperes) Maximum Load (Amperes)
15 or 20 15 12
20 20 16
30 30 24
No it seems like I might know what I am talking about here.
This is the Standard that UL has set forth for the manufacturing of these devices and the load at which they are to be tested.
When a 1500 watt portable electric heater is plugged into one of these 15 amp devices they heat and the device is destroyed. 1500 divided by 120 volts equals 12.5 amps. Let this device be in series with other devices that are carrying a load of their own and now we have more than one device that is being affected.
Now couple this with the trip curve of a breaker and we see that it is possible to load that receptacle to enormous amounts of heat and failure will occur. A general rule for the trip curve of a breaker is it will carry six times its rated current for two full seconds. It will carry three times it’s rated current for up to five minutes.
As for all this area bull hockey that has been spread around in a futile attempt to prove that back-stabbing is some awful miscarriage of the electrical trade take a look at the end of a #14 conductor and tell me what the area of that conductor that under certain circumstances can carry 20 amps continually and explain to me again about all this contact area. Are you trying to say that the contact area for a conductor must be larger than the conductor in order for the conductor to carry current? Come on now let’s get real in this discussion.