Landscape lights hack or reasonable improvement

Electromatic

Senior Member
Location
Virginia
Occupation
Master Electrician
I have a customer with about a 300' long driveway. There are about 1/2-dozen receptacles in cast boxes supported by two stubs of pipe each placed along the driveway. Plugged in to some of these receptacles are lengths of extension cord cables going to basic hardwired stake landscape lights. Some are a few feet away, some are 10-20' away. I'm thinking of getting small, waterproof, plug-in transformers to put at each receptacle and convert the cabling and fixtures to 12V. I know it sounds kind of convoluted and introduces more points of failure, but I reckon it will eliminate a good amount of potentially hazardous 120V cordage laying on the ground.
Thoughts?
I kind of wonder if the transformers might help prevent the GFCI receptacles tripping on minor faults of the cabling or fixtures on the 12V side.
(BTW, the existing receptacles are not GFCI protected and are quite full of crud, corroded, etc. I spoke with the customer about replacing them. I would plan to have individual GFCI recs at each location due to the aged wiring and overall length of the circuit.)
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
What brought up this issue in the first place?

My inclination is not to try and make it "safer". It needs to be fixed right. I like the idea of converting the fixtures to 12 V. I think i would use a blind GFCI outlet though and hardwire the transformers, and then bury the cables going to the fixtures. It seems to me that in any case you are only saving the 120V circuit.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Electrical Monke
I did a job a couple of years ago with a really long driveway and mounted the LV transformers on strut pedestal at each receptacle. I used GFCI receps and we’ve had no issues with tripping.

Here are some pics.



Sent from my iPhone using Tapatalk
 

Jon456

Senior Member
Location
Colorado
First, I would ask four questions:
  1. Is the wire to the receptacles in conduit or direct buried?
  2. What is the gauge of the wire to the receptacles?
  3. How many total fixtures are there?
  4. Are the lights simply decorative, or are some high wattage (e.g., spotlights, floodlights, security lights, etc.)?
 

Electromatic

Senior Member
Location
Virginia
Occupation
Master Electrician
I was called out because some of the lights/receptacles were not working. I found a wire capped off upstream of another location where some poorly-stripped UF in the receptacle box caused a short. The installation looks like it has been there for many years. Obviously someone troubleshot it previously but couldn't find the short that I found.
The cast boxes and the pipe stub supports are in pretty good condition. The wiring is direct-buried 12-2 UF. There are about 6 receptacles and 8-10 lights. The lights are basic pagoda-looking landscape lights with A19 lamps.
I want to go with plug-in transformers so I don't have to dig up the pipes to get another wire sleeved in to the boxes.
Basically, the wiring and boxes are pretty good. The bad is that the receptacles are corroded and not GFCI, and the cables to the lights are at 120V and mostly not buried (some lengths have subsided into the ground).
 

Jon456

Senior Member
Location
Colorado
You might consider disconnecting the UF from 120V at the source and re-purposing it as low voltage conductors for the lighting by connecting the UF to a single landscape lighting transformer. To do this, you will probably need to replace all the lamps with LEDs to reduce the total power draw so that voltage drop won't be a problem. From each receptacle box, you can run standard low voltage landscape lighting (14ga will likely be sufficient) to the lamps, connecting everything in parallel. Better-quality transformers have multiple output taps: 12V and 15V are common; some have higher taps. These allow you to compensate for voltage drop at the lamp farthest from the transformer. Just make sure your lamp closest to the transformer does not exceed the max voltage rating of the LED.
 
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