Electrical question:

How is it that an 18 AWG conductor is allowed to power 10 120 volt light bulbs? Am I missing something or is this just crazy?

Reply to
Molly Brown
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What are you looking at, specifically? LEDs don't put much load on the circuits powering them. It's the load, (amperage) that determines wire size.

Reply to
Dean Hoffman

How many watts? If they are 75w,that's just 6 amps, doesn't sound bad.

Reply to
trader_4

It should work if the average light bulb is using no more than 500mA (60W).

Reply to
Sam E

Missing something, probably...

18 AWG ampacity is 10A (50 ft) so 10 * 100W/120V --> 8+ A
Reply to
dpb

If one puts ten light bulbs of 75w or 100w on the end of a 6 ft cord that's going to be a hell of a lot of light in one place, isn't it? I'm thinking maybe it's a string of old Edison lights or similar hanging along a longer run and they are probably 75W max.

Reply to
trader_4

Here in Australia you are allowed to put up to (I think) 10 electrical outlets rated at 10A on a 20A rated cable. The Standard just assumes most of these outlets won't be in use at the full 10A current at any one time, so there is zero chance that 200A will go down the 20A cable. In any case the 20A cable is protected by a 20A circuit breaker.

I should imagine the 18AWG lighting circuit conductor is protected by a correctly sized fuse or circuit breaker, and in any case probably most of the lights won't be on together anyway.

Ross

Reply to
RMD

Not so. The circuit in North America will be protected by either a 15 or 20 amp breaker. The 18 guage wire will be a roughly six foot cord on a lamp.Noth american cords are not fused like many euro and Australian plugs. The lamp will have numerous bulbs in it - often it will be a chandelier with candellebra bulbs of 40 to 60 watts. Very uncommon for any other situation to have 10 bulbs other than decorative string lighting which are also generally 40-60 watt bulbs. In all these cases all bulbs would most likely be lit together.

If someone is worried the cord may be overloaded it is a simple matter to replace the incandescent bulbs with LEDs at about 1/10th the power consumption for the same light output.

In North America "premise wiring" - wiring permanently installed in a structure, for lighting circuits operation on 120 volts are MINIMUM

14AWG. There is no other (lighter) cabling certified for premise wiring installation in Canad or the USA and circuits are protected by a minimum 15 amp fuse or breaker, There are no breakers or fuses rated at less than 15 amps approved for residential wiring installations. Devices MAY have internal fuse or breaker protection - usually appliances - most commonly electronic devices. Motorized devices and heating devices often have thermal protection - but VERY FEW lighting devices have any protection built in at all.
Reply to
Clare Snyder

No Australian plugs are fused.

Reply to
billj

More bullshit!

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Reply to
bullshit

Yes, the democrats are out to destroy the US...which is why I'll never ever vote for a democrat.

Reply to
devnull

American code does not seem to reference 10 amp breakers as acceptable. Check NEC code reference 210.3 with the following...

"Branch circuit ratings for other than individual circuits must be

15A, 20A, 30A, 40A, or 50A."

This MAY allow for a 10 amp breaker to protect a particular hard wired/exclusive circuit such as a dish-washer or garburetor - Generally speaking "device protection" breakers, as differentiated from "circuit protection" breakers are installed in or at the protected device rather than in the panel.

Seimens ans Square D APPEAR to be the only source for 10 amp breakers and they are not (as far as I can determine) available in Canada. Not available from my electrical wholesalers.

Reply to
Clare Snyder

I thought that was 16. 18 should be more like 5A.

Reply to
Sam E

10 amp breakers are specifically for alarm circuits, not general lighting circuits. 18ga is good for 10a in a 2 wire cable or 7a if there are 3 current carrying conductors in a cable..
Reply to
gfretwell

blah blah blah

Reply to
bullshit

And for monitoring circuits (e.g. on solar panal arrays).

Reply to
Scott Lurndal

That is pretty much true as long as you are not trying to use it as an excuse to avoid the rules about "15 and 20a 120v circuits". You will have to add "device" protection for circuits that require AFCI/GFCI protection since they do not offer it in a 10a breaker.

Reply to
gfretwell

That is an interesting question. As long as the "ampacity" (14ga or larger wire) complied, I am not sure if it is a violation. This came up with the idea of putting the bedroom smokes on a 10a right after the AFCI rules kicked in on 15 and 20a 120v circuits (2002). The opinion of NFPA was you still needed to include AFCI protection but they didn't say it was illegal. At the time there was no "device" AFCI so it was moot.

Reply to
gfretwell

I was assuming Clare's cite was correct:

"American code does not seem to reference 10 amp breakers as acceptable. Check NEC code reference 210.3 with the following... "Branch circuit ratings for other than individual circuits must be

15A, 20A, 30A, 40A, or 50A."

But I just looked in the 2017 edition and 210.3 doesn't say that, it's about something totally different, so IDK what edition he got that from. I do see where they say 210.23 (A) A 15 or 20A branch circuit shall be permitted to supply lighting or other utilization eqpt, or a combination of both..... It's all irrelevant anyway, really. Does Romex exist in less than 14g? I'll bet a 10A breaker costs as much or more than a 15A too.

The original question about ten lights on 18g, I was thinking it might be a string of outdoor lights that you could put a 100W bulb in or a string of Edison lights. But others had a more common case, a chandelier that has ten of the smaller bulbs, 60W max and it's very common to see 18g wiring on those, no issue.

Reply to
trader_4

One other thing comes in to play with the lights. They are designed to be strung up in open air. This lets the wire run cooler than if in a wall or conduit with little to no air circulating to carry away the heat.

Reply to
Ralph Mowery

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