Patio String lights: Question about length.

oldalgebraAugust 26, 2012

OK. Here goes. I hope I can make myself understood.

I'd like to purchase 250 of these indoor/outdoor

LED globe lights which fit into C9 sockets.

If I purchase a 500 foot coil of 18 AWG wire with C9 sockets, can I run 500 bulbs ( with sockets every 6 inches), or 250 bulbs (with sockets every 12 inches) on a 250 foot single uninterrupted run? Or can't it be done?

The wire that the company sells is either STP-1 or STP-2, if that makes a difference.

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I might be missing something but I had a hard time following the the number of LED bulbs, length of wire, and spacing of sockets - but enough information to get the idea across of what you wish to do.

I clicked on the links you provided and it appears that the website is just an importer of these products. Since they do not provide the current requirements of each of the LED globe lights, there is no way to calculate the total current requirements of the strand.

STP-1 or STP-2 only refers to the thickness of the same type of insulation used on the 18 AWG wire and does not change the amount of current it can carry - it is typically used in consideration of the environment in which it will be used.

Your best bet is to contact the website directly with your question - and hopefully they will have the needed specifications and information you need available.

    Bookmark   August 26, 2012 at 10:56PM
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And running 120 V wireing and bulbs is gping to bring in a lot of wurles you may not want to hsvr to deal with, like burial depth of the wire.

While LEDs themselves are low voltage devices, you have chosen a 120 V product, and a type of cable not suitable for 120 V direct burial.

    Bookmark   August 27, 2012 at 9:31AM
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Thank you so much for your replies.

I will be hanging the lights, or rather draping the lights from the top of the walls to the center of the ceiling patio overhang.

I did find some information that the wire is rated at 10 amps.

I am sorry my information was so confusing. I don't understand much of the electrical "lingo" so really don't know what information is necessary to make a decision.

Again, thanks for your time.

    Bookmark   August 27, 2012 at 10:45AM
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Hi! I am a great Christmas enthusiast myself, so here's what I have learned over the years that might help you.

I have found that most SPT1 insulation wire is 20-AWG and most SPT-2 insulation wire is 18-AWG, so you might want to look for SPT2, even though the wires will be thicker. Also, even though regular 18-AWG is rated at 10 amps, you have to de-rate to 5 amps because the sockets have little tabs that pierce the insulation to get to the copper wires and that somewhat damages the strands of wire. That means your maximum per continuous strand is 600 watts (120V*5Amps), but you can cut the strand and put a female connector sold for this purpose on the end and start a new strand.

I checked you links, and they don't seem to mention wattage or current requirements, but if you order a box of 25, that information should be printed somewhere on the box or the device itself. I am assuming it will be very low, since they are meant to replace 7-watt bulbs in an effort to conserve energy. I have bought some in the past that consume .35 watt.

To give you an idea, at .35 watt you could string together 1714 bulbs. If they were the 7-watt variety, you could only string 85 together.

    Bookmark   August 27, 2012 at 11:07AM
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Thank you, thank you, thank you. That's so clear. Now I know the kinds of questions to ask the distributer.

I think I can go from here now. Bless you!

    Bookmark   August 27, 2012 at 12:22PM
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Here's the information.

The cord is indeed rated at 10 amps. So if we derate it to 5 amps, the maximum continuous strand is (120v X 5 amps) 600 watts.

The bulbs have "AMPS Usage .008 A and Watts 0.96W."

Let's round the watts to 1. That means I can string 600 bulbs.

If I use cords that have sockets every 12 inches, I'd only be using 250 bulbs.
If I use cords that have sockets every 6 inches, I'd be using 500 bulbs.
So I am well within the number of bulbs on a single run, no matter which I decided to use.


Two more questions. The site also sells Heavy Duty Green SPT-1 18 AWG wire for making custom leads and for creating blank runs between areas where you don't want to have any bulbs or sockets showing.

1. Can I safely make a two foot lead in the beginning of my run?
2, Cab I safely splice in a 5 foot plain wire somewhere in the middle of the 250 foot run?

Thank you.

    Bookmark   August 27, 2012 at 4:17PM
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If you are using this outdoors make SURE it is plugged into a GFCI.

    Bookmark   August 28, 2012 at 9:51AM
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I went right out to check. Turns out, it's not a GFCI. I'll have that changed immediately. Thanks for the heads up! It might never have occurred to me.

Everyone, thank you so much for all your help.

    Bookmark   August 28, 2012 at 10:14AM
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