dusk to dawn light problems

hvac/r- pro1 · 11-26-2012, 08:54 PM

I am working on a dusk to dawn mounted street light with the sencor on the top. the light stopped working so i thought it may be the bulb. so i changed the bulb and still no light. took the bulb out and meter test reads 122.5 v . the weird thing is it has power but will not light up. another thing is i don't hear any humming or anything. so i tried the bulb on a light i know works and it fired right up. could it be a bad ground ,loose connection or bad transformer?

**beenthere** · 11-26-2012, 09:17 PM

Moved to Electrical.

sdsester · 11-26-2012, 09:17 PM

If you are getting 122.5 v there would not be a transformer? Or is the bulb low voltage and there is a transformer between what you tested and the bulb? It sounds like your sensor might be bad and is not opening the switch.

By the way, I asked the moderators to move this to electrical. I feared it would get lost in appliances.

**beenthere** · 11-26-2012, 09:19 PM

Could be a ballast.

Is this a sodium or mercury vapor light.

k_buz · 11-26-2012, 09:43 PM

You will not get a meaningful reading by metering at the socket if there is a ballast in this fixture.

You need to take the fixture apart and meter the wires coming off the photocell to see if the ballast is getting power. If it is, you are either using the wrong lamp, or the ballast is bad.

HID lamps and ballasts must match.

11-26-2012, 08:54 PM	#1
hvac/r- pro1 Newbie Join Date: Nov 2012 Posts: 3	dusk to dawn light problems I am working on a dusk to dawn mounted street light with the sencor on the top. the light stopped working so i thought it may be the bulb. so i changed the bulb and still no light. took the bulb out and meter test reads 122.5 v . the weird thing is it has power but will not light up. another thing is i don't hear any humming or anything. so i tried the bulb on a light i know works and it fired right up. could it be a bad ground ,loose connection or bad transformer?

11-26-2012, 09:17 PM	#2
beenthere An old Tradesmen Join Date: Oct 2008 Location: PA Posts: 19,045	dusk to dawn light problems Moved to Electrical.

11-26-2012, 09:17 PM	#3
sdsester Member Join Date: Sep 2009 Location: Chicago Posts: 8,923	dusk to dawn light problems If you are getting 122.5 v there would not be a transformer? Or is the bulb low voltage and there is a transformer between what you tested and the bulb? It sounds like your sensor might be bad and is not opening the switch. By the way, I asked the moderators to move this to electrical. I feared it would get lost in appliances. __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

11-26-2012, 09:19 PM	#4
beenthere An old Tradesmen Join Date: Oct 2008 Location: PA Posts: 19,045	dusk to dawn light problems Could be a ballast. Is this a sodium or mercury vapor light.

11-26-2012, 09:43 PM	#5
k_buz Licensed Electrician Join Date: Mar 2012 Location: SE Wisconsin Posts: 3,277	dusk to dawn light problems You will not get a meaningful reading by metering at the socket if there is a ballast in this fixture. You need to take the fixture apart and meter the wires coming off the photocell to see if the ballast is getting power. If it is, you are either using the wrong lamp, or the ballast is bad. HID lamps and ballasts must match. __________________ Not a fan of the new layout. Answers based on the National Electric Code. Always check local amendments.

dusk to dawn light problems