20 AWG wire capacity

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Old 02-01-17, 09:48 AM
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20 AWG wire capacity

Hi everyone,

I am new on this forum and English is not my mother tongue, so forgive me if I am not clear enough.

I am currently building a lamp and want to power a LED strip using a 150 W driver, that runs both on 110 and 220 Volts.

I want to use a 3m long cable between the electricity plug and the driver, and was wondering if a 20 AWG would be enough to do that. Can you help me?
 
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Old 02-01-17, 09:56 AM
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Welcome to the forums.

In the States I believe the smallest gauge power cord you could use would be #18.
I'm not sure if that is the same where you live.
 
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Old 02-01-17, 09:59 AM
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Yes, 20 gauge is ample for 150 watt load at both 120 and 240 volts. You must choose cable that has insulation rated for at least 600 volts.
 
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Old 02-01-17, 10:01 AM
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Thanks a lot for your answer, PJmax.
Is that due to the safety regulations applicable in the US, or a technical requirement? Does it change if I use 110V or 220?

I am new to this world. Sorry if I am asking nonsense.
 
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Old 02-01-17, 10:20 AM
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Thanks a lot for your answer, @CarbideTipped .
What would happen if the insulation is rated for 300V?
 
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Old 02-01-17, 10:30 AM
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Ul 62

Table 6.6 gives guidance here. "Decorative Lighting" cable is called "XTW" cord, and 20AWG is covered for "non-grounded" lamps. That is, "double insulated". 300V rating, and the PVC insulation thickness is further specified.

Does the LED driver require earth ground? Not positive, but I don't think there is any 3 wire/grounding cord in 20AWG that will comply.
 
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Old 02-01-17, 11:06 AM
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It does not require earth ground. And it is powering a LED strip that takes 100 W (12V).
Where can I find Table 6.6?
 
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Old 02-01-17, 11:53 AM
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300 volt wire cannot be used on 240 volts. If you want to limit your lamp to use on 120, 300 volt wire is OK.

Please add your location to your profile so we can try to make sure our answers are appropriate for your area.
 
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Old 02-01-17, 02:31 PM
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300 volt wire cannot be used on 240 volts.
Do you have an authoritative source for that statement?

To my knowledge the voltage rating on wire insulation relates to the maximum voltage compared to the earth. 240 volts in the US is only 120 volts to ground (earth) and even in those areas where the "standard voltage" is 240 with one side grounded it would still be less than 300 volts.

600 volt rated insulation would only be required (in the US) IF the system was a three-phase delta with a "wild leg" above 300 volts to ground or any three-phase system with 480 volts phase to phase.
 
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Old 02-01-17, 06:04 PM
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The wild leg of a 120/240 volt three phase system is about 208 volts to ground. 300 volt wire should be fine. 600 volt wire is OK too, just overkill.
 
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Old 02-01-17, 06:19 PM
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It's a crazy world. DC boat wire is rated at 600V. Boats that are running a 12V battery, that is. i grabbed some 500kV wire not long ago. It wasn't insulated. I'm not willing to correlate voltage rating with anything.
 
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Old 02-01-17, 06:25 PM
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Nope. Thought this was in NEC but can't find any such limit. Mea culpa.
 
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Old 02-01-17, 06:26 PM
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Voltage is voltage no matter if it is AC or DC. 600 volt wire is quite common. The 500 KV wire was likely for overhead wires which would not have any insulation.
 
 

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