Burial Wire Labeled As "Low Voltage". Why ?


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Old 04-13-24, 05:02 AM
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Burial Wire Labeled As "Low Voltage". Why ?

Hello,

Looked at Amazon for some approved direct burial wire to run in a slit in the lawn
from house to an outside lantern pole light.
Probably use a 100 Watt Bulb. 110 V ac

Want to use 14/2 to be on the safe side.

Was surprised to see that they all the direct burial wires are labeled "low voltage" applications.

But, shouldn't (any) 14/2 be fine for 110 V ac ? (it sure is for inside the house)

Why do they label as "low voltage" ?

Thanks,
Bob
 
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Old 04-13-24, 05:36 AM
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It is the insulation. Low voltage is thinner insulation.
 
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Old 04-13-24, 05:44 AM
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You are looking at the wrong wire. I'm sure an electrician here will correct me if I'm wrong, but the wire you need is UF-B. A slit in the lawn will not meet code requirements. Direct burial line voltage wire must be at least 2' deep.
It would probably be cheaper and easier to convert your post to a low voltage LED.
 
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Old 04-13-24, 11:53 AM
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Correct.... you need to use 14-2 w/gr UF cable...... 14-2UF/B
 
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Old 04-13-24, 11:55 AM
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Direct bury can be as shallow as 12" if gfci protected at the source. The max limit on size is 120V 20A circuit.
 
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Old 04-13-24, 01:25 PM
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Is that new? I buried a cable 4 years ago to a detached garage. At that time I had three options that I knew of. I could bury it unprotected at 24", in a PVC conduit at 18" and I think (not sure) I could bury it at 12" in concrete.
 
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Old 04-13-24, 02:34 PM
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Not new. Your garage cable is probably a feeder, not a branch circuit, so would not qualify in any case.
 
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Old 04-14-24, 06:13 AM
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Standard NM cable (Romex) and UF cable (as examples) have insulation rated at 600 Volts maximum. Your cable is probably has insulation rated at 300 Volts maximum. It might appear that 300 volt cable would be suitable, but it is not. Cable for alarm systems is rated 300 Volts and they use 12 or 24 volts.

The 300V marking was removed from low voltage cable a number of years ago. The story I heard was that people were saying, " 300 Volts? I'm only using 120 Volts so this cable is good." The codes are all about keeping you from killing yourself or someone else by electrocution and fire.
 
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Old 04-14-24, 09:41 AM
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I could bury it at 12" in concrete.
Under 4" of concrete the depth for direct burial cables is still 18" unless it is 20 amps or less and GFCI protected.
 
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Old 04-14-24, 03:58 PM
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Not new. Your garage cable is probably a feeder, not a branch circuit, so would not qualify in any case.
If the feeder to the garage is a single 120V 20A circuit then the 12" burial depth with GFCI protection at the source does qualify. A feeder of this nature is a branch circuit.
 
 

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