300 foot landscape light situation

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Stevenfyeager

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United States, Indiana
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electrical contractor
someone ran a 300' #12 landscape wire to gate post lights, 12 volt transformer. Customer says the lights worked for a while. I'm trying to explain voltage drop issues. #10 in my calculator still doesn't get it down to 5%. Other than running 120 v out there, any suggestions ?
 
you'll want to run 120v to the gate and mount the transformer there; 300' is economically too far to run 12v.
 
If it is a lot of work to run the 300', you could consider running a slightly higher DC voltage supply on the existing low voltage wire (e.g. 24 - 48 V) and use a DC-DC converter at the point of use to regulate the 12V DC.
 
I'm guessing that the current low voltage wiring method cannot be converted to 120 volts so maybe you could shift to 24 volt lighting.
 
I remember on long runs using #8 landscape wire for the major portion of the run. Perhaps you can rewire the first 150-200'.

So what happens when the lights go out? Do they come back on after the transformer resets the thermal overload? What load do you have on the transformer and what size is the transformer? It may be the transformer is undersized also.
 
Sounds like duplicate problems.. if they worked "fro a while" you need to verify if you have any voltage at all. If the lamps are not LED type, changing to LED lamps should improve your voltage drop problem.
 
As noted more info is needed. You also may be able to use a different transformer that has various taps to boost the output voltage which will compensate for VD.
 
The transformer does have some options from 12 up to 15 V but right now we’re getting 12 V at the transformer where this circuit was connected and only 1.5 V at the gate.
Which tells me probably the wire is damaged because that’s a lot more than the voltage drop that we would expect. Thank you for your advice.
 
Stevenfyeager said:
The transformer does have some options from 12 up to 15 V but right now we’re getting 12 V at the transformer where this circuit was connected and only 1.5 V at the gate.
Which tells me probably the wire is damaged because that’s a lot more than the voltage drop that we would expect. Thank you for your advice.
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Or there's a partial short/overload causing excess current.
 
Stevenfyeager said:
The transformer does have some options from 12 up to 15 V but right now we’re getting 12 V at the transformer where this circuit was connected and only 1.5 V at the gate.
Which tells me probably the wire is damaged because that’s a lot more than the voltage drop that we would expect. Thank you for your advice.
Click to expand...
Your wire is too small. What type of lights are they? Led, incandescent? How much wattage is there. The fact that there is only 1.5v at the end of the run can be because there is too much wattage for that size wire. It is a voltage drop issue or what Larry stated.
 
It’s always going to be what Larry stated. I can’t even count how many times he’s solved a problem for me. But it might be worth removing all the bulbs and then checking the voltage. If the situation improves at all you could consider the 15v tap and try to get LED bulbs that fit the lights. This stuff is a pain I just dealt with it. It’s very easy to get to 300 ft but usually you see 6 or 8 volts, not 1.5. I would definitely use process of elimination and see if the problem goes away as bulbs are removed.
 
The old bulbs were “burned out looking “ my worker said. He replaced them with 4 W LED new ones. I would have never tried to run 300’ of #12 wire of any kind. My worker actually measured 320’ with a measuring tape this morning instead of his stepping off 300’ last time. We did a lot of work for this customer 12 years ago, he asked me at that time the price for getting 120 V to the end of the driveway, he had sticker shock. Apparently some years later a landscaper told him ‘that’ll be no problem.’
 
LarryFine said:
Or there's a partial short/overload causing excess current.
Click to expand...
Doc13067 said:
It’s always going to be what Larry stated. I can’t even count how many times he’s solved a problem for me. But it might be worth removing all the bulbs and then checking the voltage. If the situation improves at all you could consider the 15v tap and try to get LED bulbs that fit the lights. This stuff is a pain I just dealt with it. It’s very easy to get to 300 ft but usually you see 6 or 8 volts, not 1.5. I would definitely use process of elimination and see if the problem goes away as bulbs are removed.
Click to expand...

Yes, properly working lights of any kind that are intended for 12V are not going to be drawing much current, and certainly not enough current to cause this much voltage drop.
 
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