I wish to run 4 x 7w LED globes in in parallel using one 12VDC power supply. What cable would I need to safely do this?

 

Current is (4 x 7) / 12 = 2.33 A.

16 ga is called for.

Bob

 

I wish to run 4 x 7w LED globes in in parallel using one 12VDC power supply

What length of wire will you need?

 

Current is (4 x 7) / 12 = 2.33 A.

16 ga is called for.

Bob

16 AWG?

 

What length of wire will you need?

6meters/20ft

 

16 AWG?

Standard lamp cord. A lower gauge is a thicker wire, and more (thickness) is better. So a 14 gauge would also be OK, but not an 18.

Don't forget the mechanical properties, for instance if there is contact with the ground, exposure to sunlight, rodent bites and so forth.

 

6meters/20ft

For 20ft #18 would be fine. That's a max resistance of only .255 ohms at the end of the wire. You would lose about 1% of the 12 volts at that distance.

 

16 AWG is larger than I anticipated, I am currently feeding the transformer 240VAC using 16AWG or 1.5mm cable. I guess then I can use the same cable from the transformer to the lights then.
I currently have 4 x iron core transformers powering 4 x 7w LED. They use to power 50w halogens, plan is to run all 4 LED of the one transformer.

 

plan is to run all 4 LED of the one transformer.

Should be no problem.

 

16 AWG is larger than I anticipated, I am currently feeding the transformer 240VAC using 16AWG or 1.5mm cable.

28W at 240V is just 117mA. So 16 gauge for 1.5m is "overkill" based only on the amperage. But again, 16 is a standard and there's nothing wrong with overkill.

 

28W at 240V

That's 240VAC into the transformer and 12VAC out of it.

 

The point is that the secondary is higher amps and so it requires a larger (smaller AWG) wire than the primary.

Bob

 

#18 wire is a very common size for electrical appliances, I have a power washer with a 15 foot cord of #18 wire, and that is no problem at all.And #18 is both more common and a lot cheaper than #16 wire.

 

@MisterBill2 is correct and I misspoke earlier: standard lamp cord is 18 gauge. And it’s fine for a 2-3A load. That’s 240-360W on a 120V supply, and not unusual for a lamp.

 

The chart I looked at gave 2.3 as rhe max Ampicity of 18 gauge wire, so right on the edge for this application..

Bob

 

The chart I looked at gave 2.3 as rhe max Ampicity of 18 gauge wire, so right on the edge for this application...

For the 20ft., I'd also prefer going bigger. But a 300W bulb on a typical 6' lamp cord used to be a pretty normal thing.

 

The chart I looked at gave 2.3 as rhe max Ampicity of 18 gauge wire, so right on the edge for this application..

Thanks, I already have 1.5mm cable (which is 16 gauge equivalent) at hand. Better to go bigger than risk it.

 

W are talking about a power cord, NOT about a bunch of wires in a conduit in a high ambient area. There are a number of different ampacity tables that depend on the environment and the insulation.