600 C-9 light bulbs

We are putting light bulbs on a large outside tree in a city park. We have six 100 foot strings of 100 C-9 lights. We have two 20 amp GFI circuits available. I plan to put 300 lights on each circuit. My math shows 2300 watts available and C-9 bulbs use 7 watts. This comes to

2100 watts. I will use 12 guage extension cords. The light strings and bulbs are commercial grade. This all looks good on paper, but I am worried because there is not much room for real world error. Does anybody have experience with this many lights? Wasn't there a movie about a guy causing a large scale blackout when he threw the switch on his house decorations? I don't want to be that guy. Any help you can give me would be appreciated. Thanks, Gus
Reply to
gus
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Reply to
buffalobill

The normal rule is you don't put a load greater than 80% of circuit capacirty itf it will be on longer than 3 hours. Christmas is usually when the NEC goes on vacation though. If you spread these out across 6 cords, plugged into the receptacles directly I don't really see a huge problem thouigh since, technically it is a

700w load and a 1400w load on each, not a 2100w load. The circuit itself should take it.
Reply to
gfretwell

Fortunately circuit breakers do not take holidays off. They are only rated for a maximum of 80% continuous load of 3 hours or more. Depending on the age, quality, and condition of the circuit breakers you may not get them to stay on for that long. That's about 16 amps for a 20 amp circuit.

Reply to
John Grabowski

I think I remember that from "National Lampoon's Christmas Vacation" and the blackout ended when someone at the power plant threw a switch labeled "Emergency Nuclear Power".

That was followed by someone saying "Don't look directly at the house".

I have used 300 around my house, but that was divided among 3 circuits (shared with other lights). I consider the load to be 6A per 100. That's a little safety margin.

18A load from lights might be too high for one circuit, considering the extra current drawn by lights when they're cold.
Reply to
Mark Lloyd

I don't know of any modern name brand breaker that will not hold 100% of the rated amps ... if you can believe the manufacturer ratings

Reply to
gfretwell

First problem I found - C9 bulbs consume more than 7 watts, and I have the impression of traditionaly 10 watts!

I would allow for 10 watts per C9 bulb!

- Don Klipstein (Jr), ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

Mark Lloyd wrote:I hel;ped my neighbor a griswald type a few years ago. He was using his main plus a sub panel drawing over 120 amps. We had to balance the loads since breakers were tripping.

He got a near 1000 buck electric bill and now does nearly nothing.

He had made the news and created a traffic problem but I miss it.

He offered to do it again but power it from my home...

He literally lit up the neighborhood!

Reply to
hallerb

I was really thinking "9" in C-9 was the watts but the way they rate things these days I wouldn't bet on anything. I doubt the quality control is that precise to start with. The safest bet is 3 circuits if you can come up with another 20 amps somewhere.

Reply to
gfretwell

Dim them slightly for much longer life.................

Reply to
hallerb

C9 is a designation of bulb style/shape and diameter, and not wattage.

C means "candle flame shape". The "9" means maximum overall diameter, in 1/8ths of an inch (meaning 1.125 inches).

C9, A19 and things along these refer to bulb shape/diameter.

There is a letter designation for bulb shape, and a number designation of bulb diameter in 1/8's of an inch.

A has 2 stories behind it, 1 saying "arbitrary" and 1 meaning "average". A lingering story is that "average" is between "PS" (see below) and "S" (see below).

B is supposedly "Blister", but some sort of oval shape.

C means "candle flame" shape.

E means ellipsoidal.

F means a flame shape - maybe more bottom-fat than C.

G means globular/spherical.

GTL means an incandescent penlight bulb having a short tube protruding from a spherical bulb with the short tube having a lens.

K is some specific reflectorized bulb design that I sense as being good for more compact incandescents.

PAR means "Parabolic Aluminized Reflector" - traditionally a narrower beam spotlight.

PS is "pearshape" - usually a higher wattage bulb that has a tubular "neck" between the base and the "main bulb portion".

R means "reflectorized bulb" - usually a floodlight or spotlight design.

S is a shape more common for some automotive types of bulbs and some more ancient designs of bulbs - "S" means "straight-sided" - like an "ice cream cone".

T means any of a significant variety of tubular shapes, for both "single-end" and "double end" lightbulbs! May include some Philips ones from production lines previously owned by Westinghouse, as well as whatever else (bigtime available) is "T-bulb"!

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

The C9 Christmas lamps used to be 9 or

10 watts, however, > >
Reply to
Art Todesco

For what it's worth, that's 15.98 amps at 120 volts, or right at the 80% of the circuit rating that you were told was the limit, several posts ago...

Reply to
Doug Miller

There is a reason they're called c NINE. They are 9w each. duh.

Reply to
Steve Barker LT

uh huh. ok, pile 'em on and see.

Reply to
Steve Barker LT

Yeah, you would think that -- but you would be wrong.

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C9 simply specifies the shape and size of the glass bulb.

Reply to
Doug Miller

With the ones I measured, it was very close to 7W. However, I did notice a significant variation between bulbs, so 10W isn't too unlikely.

Reply to
Mark Lloyd

Or use C7 bulbs, which are closer to 5W.

Reply to
Mark Lloyd

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