Point load on NM wiring:
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I often see one in every room in a 1950's house.
Oh, you mean high-amperage loads!
Point load on NM wiring:
View attachment 2552152 View attachment 2552153
I often see one in every room in a 1950's house.
And it is up to the buyer to make sure it is done. It is their loan not the sellers loan.
I actually meant high-amperage loads made of a group of lower-amperage loads plugged into a single point (one receptacle with power strip(s) plugged in) on a circuit, but the result is the same.Oh, you mean high-amperage loads!
I actually meant high-amperage loads made of a group of lower-amperage loads plugged into a single point (one receptacle with power strip(s) plugged in) on a circuit, but the result is the same.
I prefer running a new circuit for such loads (as well as heaters) which both serves the loads better and conserves the house's GP receptacles for the usual expected loads like room lighting, etc.
When I was a helper, one of the first jobs I was given to do on my own was to install one new receptacle in each room, each on its own circuit, for portable heaters.That would be a neat trick... predicting where in a house someone is going to plug in a 1500w heater.
I would tell them to pound sand. This is my price, take it or leave it!
And tell YOUR realtor to bring around more qualified prospects. No Millennials!
-Hal
When I was a helper, one of the first jobs I was given to do on my own was to install one new receptacle in each room, each on its own circuit, for portable heaters.
Agreed I dont even see how the 1500W ones are legal with a 5-15 cord cap, as they are a continuous load.I do my best to discourage portable heaters, especially in dwellings in general living spaces. They are fire hazards period.
You can buy one that is expensive, claims to not have any hot exterior surfaces etc, but reality is they still draw ~900-1500 watts, and still seen many of those units that still melt the plug/receptacle connection point if it is not in excellent condition.
You can't compare them to a similar wattage kitchen appliance or even a hair dryer, as those items typically have limited run time compared to a space heater which in some cases might run nearly 24/7 and that poor connection at the receptacle never cools down.
Agreed I dont even see how the 1500W ones are legal with a 5-15 cord cap, as they are a continuous load.....
If the heat loss from the space is greater than the output of the heater, it will be a continuous load. The thermostat will never cut it off.As long as there's a thermostat in the unit, it's not a continuous load.
If the heat loss from the space is greater than the output of the heater, it will be a continuous load. The thermostat will never cut it off.
I get what you are saying, but I really think portable heaters are different. Far more often than not, I see portable electric heaters in situations where the T-stat will never be satisfied. FWIW even article 424 stuff is considered a continuous load, no sure why, even though i is more likely to be larger and appropriately sized for the heating load.You could make that claim for just about ANY load. A sump pump could be flooded and the float switch will never turn it off. An oven door left open so the the elements will never turn off. A light switch could get left on.
The NEC definition of a continuous load is "A load where the maximum current is expected to continue for 3 hours or more." Not possible... just expected.
If you go down that road, then every load on the planet will, one way or another, suddenly be considered continuous. You really want that?
Circuit sizing for this use case is 422.10(B) which just sends you to 210.23 :422.1 Scope. This article covers electrical appliances used in
any occupancy.
(B) Circuits Supplying Two or More Loads. For branch cir-
cuits supplying appliance and other loads, the rating shall be
determined in accordance with 210.23.
branch-circuit ampere rating =(1) Cord-and-Plug-Connected Equipment Not Fastened in
Place. The rating of any one cord-and-plug-connected utilization
equipment not fastened in place shall not exceed 80 percent of
the branch-circuit ampere rating.
Cord and plug connected loads over 1440 W can be 240V in a dwelling unit, like window AC units commonly are.210.6 Branch-Circuit Voltage Limitations. The nominal volt-
age of branch circuits shall not exceed the values permitted by
210.6(A) through (E).
(A) Occupancy Limitation. In dwelling units and guest rooms
or guest suites of hotels, motels, and similar occupancies, the
voltage shall not exceed 120 volts, nominal, between conductors
that supply the terminals of the following:
...
(2)Cord-and-plug-connected loads 1440 volt-amperes, nominal, or less...
These are not intended to be exact values. No one cares about a difference of less than one amp. These are also just heating elements so there is no possibilities of problems even when the voltage is too low.Yeah I agree 20A 120V would just get cut off;
however those 1500W heaters dont meet code on a 15A 120V general purpose residential circuit continuious load or not.
Here is my code interpretation:
424.1 states it only applies to fixed electric equipment used for space heating so its out.
A portable heater falls under 422:
Circuit sizing for this use case is 422.10(B) which just sends you to 210.23 :
210.23 states that
branch-circuit ampere rating =
15A X 120V = 1800W
The rating of any one cord-and-plug-connected utilization
equipment not fastened in place shall not exceed:
1800W X .8 = 1440W.
QED
The 1440W here lines up with us being allowed to use 240V in 210.6:
Cord and plug connected loads over 1440 W can be 240V in a dwelling unit, like window AC units commonly are.
The best solution for use of portable heaters ( I love mine in my office) would be 240V 15A over 1440W:
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but unfortunately they are not manufactured.
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