ECN Forum Forums Code Related Discussion NEC & other Code issues 20A receptacles on a 15A circuit.

I bet that mower is not pulling anything close to 13a unless you are mulching the garden hose.

earlydean ---

I allow the courts to deal with those who disagree with me about code issues.

iwire ---

13amps is simply more than 80% of 15amps and I believe that would require a 20amp circuit. (You can fill in any details of use to make this statement true.)

George, as Scott touched base on, all you would have to do is take a break from mowing every 179 minutes to keep your 15 amp circuit legal.

Roger

When I was learning to use the parachute, we were told the 'chute needed a minimum of 200 ft to work.

Now, I suppose there is someone out there who will claim to jump all the time from 190 ft, and never had a problem. Or 180. Or 170.....

The point is, you can shave the rules all you like, but sooner or later you're going to run out of luck- and go SPLAT!

In another thread (damaged extension cords), the tale is told about a tile saw that didn't work well, at the end of 300 ft of #16 extension cord. Sure, you can put on a smaller pug, use a smaller circuit, and push things to the max- but something will suffer.

Manufacturers aren't entirely stupid. If the product is listed by someone like UL, the rating agency may very well have insisted upon a certain plug. If a product comes with a 20 amp plug, well, that is the manufacturer's way of telling you that the thing needs a 20 amp circuit. @) amp breaker, 20 amp wire, 20 amp receptacle. And, even then, even larger wire may be wise (if the run is long enough).

John, you have hit the nail on the head.

The truth in labeling (or lack of) may come to play in a manufacturer overstating horsepower or performance of a tool, (Tim the Toolman mentality) but if the tool is listed by a NRTL it would come with the proper cord cap to accompany it's listing.

I have a 120v table saw with a 15 amp cord cap that boast a 3hp max output (play on words) that I use on a 20 amp circuit, and we know that a true 3 hp motor wouldn't really work on this circuit.

Roger

I will echo that label "power inflation"
Campbell Hausfelt had to give me an air nibbler (or some other tool from the catalog) because of a class action suit about the labels on their compressors.
Mine says 6.5 HP with a NEMA 5-15 plug.
I did a little informal study of hair dryers a while ago, checking every one I could find with my Fluke clamp on. None pulled more than 12a, in spite of labels up to 1800w.

In the case of this mower, I am sure the 13a is FLA and perhaps a generous cushion. Most of the time a mower runs at a small fraction of full load and we know article 430 lets us use 310.16, not 240.4(D) when we size conductor, so you have to put on your thinking cap and pinch your nose tight when you read 210.23(A)(1)"Cord-and-Plug-Connected Equipment. The rating of any one cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating."

I have an electric smoker with a 1650w element, a U/L tag and a NEMA 5-15 plug.
From the number of melted 16ga extension cords, damaged receptacles and tripped breakers in it's path before I inherited it, I think that is an accurate label. Go figure.
I know it never caused me a problem on a dedicated 20 with a spec grade receptacle.

[This message has been edited by gfretwell (edited 11-09-2005).]

"I will echo that label "power inflation"

Funny you mention Cambell Hausfeld. I have a particular gripe with my CH compressor too,
5HP with a 5-15 plug and 15 FLA yeah sure 1800W. Even if the motor was 100% efficient it cant be more than 2.4 HP. I guess if I hooked it up to 240V it might hit 5 HP as it burns out.

I should point out that I agree that the NEC disallows 20amp recepts in this case. I simply am trying to say that from an engineering standpoint a 20amp recept is not going to cause any problems that can not be caused using 15amp recepts.

I only have an old code book here. It seems to allow 50amp recepts on 40amp circuits.

Except for the fact that it will be real difficult to get the 20 amp plug in the 15 amp recept.

"I only have an old code book here. It seems to allow 50amp recepts on 40amp circuits."

That is a fairly common setup for electric ranges, at least it is in FL. I see no problem in this case. For instance, I have an arc welder that draws 37 Amps at full range. This precludes the standard 30 amp recepticle, yet it doesnt justify the expense of stepping up to 6 ga and a 50 Amp Ckt. However there I saw no problem running #8 and a 40 amp breaker with a 50 Amp socket.




[This message has been edited by IanR (edited 11-15-2005).]