Safely turn Off Power

[MSG1968]

Main Diagram.jpgHi All,

we have a property we moved into, that has solar. I have a few lights that have multiple switches, and one has blown, and since I don't know if the switches are in an off position, how does one turn off power to ensure it's safe to change a globe? Thank you.

SMA Sunnyboy
SB1700 Inverter

Mark

[SunEagle]

I am also a little confused. The drawing of that system indicates it is for a pool heating system and not your house power so how is it affecting the light you want to replace?

Otherwise there is a pair of DC switches between your panels and inverter along with a couple of single pole AC switches between the grid and your inverter. I would say you turn off one of the DC switches and one of the AC switches to isolate your inverter. But that still may not turn off the power to the light that you want to replace.

[sdold]

Hi Mark, are these the kind of light switches where you have a switch at each end of a hall, or room, and you aren't sure which one is bad because the light won't come on at all?

Normally you would turn off the branch circuit breaker before working on a switch, receptacle etc. But since you can't confirm you've shut the correct one off because you can't see the light turn off, it's safer to turn off the main breaker instead, shutting the whole house off. It should be the big breaker located above all of the other breakers in your panel. You could also measure from Neutral to each hot wire at the switches to see if they are off.

Turning the main breaker off should also shut down the solar array, but to be safe follow SunEagle's advice above.

Edit: I just re-read your question, are you simply changing a light bulb (globe)? Can't you just unscrew it and screw another one in without turning off the power?

[peakbagger]

My guess is we are overthinking the question. It looks like a plain jane grid tied solar system. It would be tied to the main panel of the house with a labeled individual circuit breaker. If that breaker is clicked off, no power is going into the main panel from the solar system. Note the main panel is still energized by the utility. Every circuit in the house is tied to an individual breaker in the panel but many of them will be combined into one breaker which may or may not be labeled well. Ideally you turn off the breaker to the circuit that supplies the light. For the safety conscious you can buy a voltage tester, a device about the size of a cigar that detects if a circuit is live by holding the tip up to the wiring. It chirps if there is voltage. On occasion circuits or junction boxes can get energized from two separate circuits usually accidentally. A voltage tester will warn the user of that problem.

[MSG1968]

there is a hot water solar system, and I believe a general solar system for general power, for the house, and back to the grid if unused. I'll take a pic of the switches in the powerboard outside, if that helps. thanks.

yes, I'm just wanting to change a globe, but since it's a hallway light, with a power switch at either end, I'm not certain the power to it is switched off. I always thought you were required to only remove globes when the power switch is off, for safety reasons? Thanks.

[Mike90250]

Nowdays, it's rare for a light bulb to explode when screwed in or out. The one thing that can happen, and you will wish the power is off for, is the cement holding the glass to the threaded metal base, comes loose and you twist the leads till they short . But if you carefully test the bulb and if it unscrews properly, you should be all set