I’m doing a little project. I’m basically trying to use an extension cord to wire it to light bulb receptacles for a display in an entertainment center. I’m wondering how many bulbs would be safe to wire to a single standard lamp cord?
It depends on several factors. To be precise you’d need to know the current rating of the cord and the wattage of the bulbs.
Generally the code will allow you to continuously load a conductor up to 80% of it’s rating. Since you’re planning to use all your outlets at the same time a rough guess is 8 lamps on one 15-amp cord but that’s assuming the breaker for the outlet the cord is plugged into is doing nothing else but powering your lamps. All those lamps are on the same breaker as whatever else is on that circuit so you have to keep that in mind too.
If you can provide a bit more information we could give you a better idea.
It’s not the quantity of bulbs but rather the power they consume. Many lamp cords are 16-gauge, which in good condition is generally thought to be capable of carrying 10 amps provided the length is not excessive. Assuming 120v (as for the US) and using the 80% factor noted by HKF, this means the total wattage of all bulbs should not exceed 1000.
If you used florescent or LED lamps rather than incandescent ones you could put more of them on the circuit. Unfortunately, I don’t know how many more you could put on.
This would again be determined by the total power consumed.
Some other considerations:
1000 watts of incandescent bulbs will be introducing a LOT of heat to the immediate environment. Perhaps 90% of the power is lost to heat.
Some fluorescent bulbs emit a lot more ultraviolet light than others and almost certainly more UV than incandescent or LED sources. This can be worrisome for delicate items like antiques, paintings, dyed textiles, etc. Another disadvantage of fluorescents: most can’t be used with dimmers.
For an entertainment center, I’m picturing a greater quantity of smaller lights with total wattage well below most safety margins. I’d think you’d do well with LED lighting or maybe 12v halogens. Halogens also emit some UV but it’s not usually too bad, esp if filtered.
This scares me. When I worked for a department store the display department was always making up things lik this. I got where I would not change the lights in them because of the wiring. If you do not know how many lights or watts you can connect I sugest tht you should not be wiring one up. What about a ground wire are you going to add one for safety.
Had two show case once that I installed, because of the place where it was put I put whips on them with a three wire cord instead of hard wiring. Two weeks later I got a call that customers were getting a shock off the show case. Display had unpluged one show case from the outlet. Plugged in a two wire extension cord:smack: then pluged in the show case and some other lighted displays using 2/3 adaptors. I got my fluke meter out, with the show case ungrounded it had a stading voltage 90 volts between the metal of two show cases. They were lucky someone with a weak heart did not put one hand on each show case.:smack:
Becareful with what you do when you do not understand electricity.