LED Driver/Power Pack

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Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
I typically place a receptacle in a lower cabinet. Preferably sink cabinet, but if not I put one at 28" to top of box in another cabinet, and stub wires next to it.

But earlier this year I had a customer who wanted me to stub it above the cabinet. When I went back to do the finish, he supplied his own LED strips and Driver, which was a plug-in block. So I put a surface mounted plug above the cabinet, and he didn't like it because he could see it. So I cut a plug into the wall, and he didn't like it because he could see it. So then I cut a plug into the back of the upper cabinet, drilled a hole in the top to run the low voltage wire in, and made the connections inside the cabinet. And he didn't like the way it looked inside the cabinet 😂😂
I've had a few (very few) customers like that!
On a side note, I've had the driver powered up for about 4 hours and it's still showing 24V, still no load or dimmer though.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
That is a big difference ...
Test Under load and measure the DC current to confirm you are not going into current limit mode using the install site loading.
I don't have a 24V load here to test with and it will be a while before I'm back at the job site. I can't just run over there as it is close to an hour drive from me. I may try to come up with a load to test with even if I get another driver. The specs on the driver says that if overloaded it will correct itself after the load is reduced. Said basically the same for under-voltage and short circuit on the load side.
 

farmantenna

Senior Member
Location
mass
I typically place a receptacle in a lower cabinet. Preferably sink cabinet, but if not I put one at 28" to top of box in another cabinet, and stub wires next to it.

But earlier this year I had a customer who wanted me to stub it above the cabinet. When I went back to do the finish, he supplied his own LED strips and Driver, which was a plug-in block. So I put a surface mounted plug above the cabinet, and he didn't like it because he could see it. So I cut a plug into the wall, and he didn't like it because he could see it. So then I cut a plug into the back of the upper cabinet, drilled a hole in the top to run the low voltage wire in, and made the connections inside the cabinet. And he didn't like the way it looked inside the cabinet 😂😂
These customers suck. " YOU TOLD ME TO PUT IT ABOVE THE CABINETS!!" You'd see nothing in the sink base , dumb.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
These customers suck. " YOU TOLD ME TO PUT IT ABOVE THE CABINETS!!" You'd see nothing in the sink base , dumb.
That's almost word-for-word what I told him 😅

Above the cabinet isn't bad if the top is recessed and there's crown molding sticking above. Gives about 3 inches to hide stuff.

But this guy intentionally ordered cabinets with a flat top and no trim above. I had no idea that's what he was getting. Euro style, he called it 🙄
 

Flicker Index

Senior Member
Location
Pac NW
Occupation
Lights
Rope lights are made up of a number of separate parallel loads. Think of it like a rope ladder with each rung being its own 6 LED+ resistor (or active ballast) that goes across the sides. If you're seeing 0v across the line at the power supply with the load connected, you have a dead short somewhere. If you're measuring 1.9v, then you might have the "second to last" segment flipped around causing it to be connected "back to back" rather than "front to back" which might cause it to jam on the polarity protection diode and causing the power supply to go into protective mode. If it was working fine until the last piece was connected, have you tried with that last segment detached/bypassed?

You could use any incandescent lamp as a dummy load.

Any respectable LED power supply will tolerate short circuit on the load side indefinitely without failing. These power supplies are class 2 and even the ropes' reverse polarity protection should withstand being hooked up backward without damage. If these ropes were powered off of something like a car battery, then a short on the other end could cause the traces on the strip to melt or catch on fire.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Rope lights are made up of a number of separate parallel loads. Think of it like a rope ladder with each rung being its own 6 LED+ resistor (or active ballast) that goes across the sides. If you're seeing 0v across the line at the power supply with the load connected, you have a dead short somewhere. If you're measuring 1.9v, then you might have the "second to last" segment flipped around causing it to be connected "back to back" rather than "front to back" which might cause it to jam on the polarity protection diode and causing the power supply to go into protective mode. If it was working fine until the last piece was connected, have you tried with that last segment detached/bypassed?

You could use any incandescent lamp as a dummy load.

Any respectable LED power supply will tolerate short circuit on the load side indefinitely without failing. These power supplies are class 2 and even the ropes' reverse polarity protection should withstand being hooked up backward without damage. If these ropes were powered off of something like a car battery, then a short on the other end could cause the traces on the strip to melt or catch on fire.
Thanks and welcome to the Forum!
Where have you been?
We have a ton of LED lighting questions!
 

WasGSOHM

Senior Member
Location
Montgomery County MD
Occupation
EE
Just my 2 cents.
LED brightness is proportional to current so they are driven by current sources rather than voltage sources.

I'd check the driver current with a series resistor and V meter or a clampon, while changing the load. It's a nondestructive test and might give some clues.

Try to interpret each result you get on the fly.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
The power supply/driver has been returned and a new one has been purchased. I won't be back at the site for a few weeks to install it. So nothing new to report as of now.
 
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