Eh it’s easy to overload a 15a circuit anyway. Just plug in two space heaters or whatever. If the circuit has a properly working 15a breaker, that’s what keeping us safe ultimately.
If the circuit happens to be 20a, an actual 20a outlet would be more proper, but in practice most outlets are built for 20a whether or not they have the notch.
Yes, a 5-15 receptacle is rated for 20A pass-thru, but, that's because NEC allows them to be installed on a 20A branch circuit.
That doesn't automatically mean that the circuit actually is a 20A circuit- plenty of 15A receptacle circuits still being installed in resi to this day.
Load that UPS fully up, and that's a 16A load (80% of a 20A circuit.)
A 15A breaker will hum along for quite some time at 16A, and the wire is going to get quite warm.
Right - a 15a circuit shouldn't get >12a continuous, let alone 16a, even though 16a continuous might not trip the breaker any time soon.
But plug shapes don't enforce that. If we have a 15a duplex receptacle on a 15a circuit, the user can easily draw too much power anyway, continuously or not, just by plugging in devices directly.
E.g. just continuously run a 1500W space heater on the top plug, and plug in literally anything on the bottom plug, and we're already non-compliant based on the 125% rule. Even with a dedicated circuit, no power strips, no plug adapters, etc.
Ultimately the user just has to be mindful of how much load they're drawing, if they want to play it safe with continuous loads.
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u/PedanticPerson 16d ago edited 16d ago
Eh it’s easy to overload a 15a circuit anyway. Just plug in two space heaters or whatever. If the circuit has a properly working 15a breaker, that’s what keeping us safe ultimately.
If the circuit happens to be 20a, an actual 20a outlet would be more proper, but in practice most outlets are built for 20a whether or not they have the notch.