what amps allowed thro' 38 swg ?

[tim_ber]

what amps allowed thro\' 38 swg ?

I need to send 75mA thro' to some leds and I am wondering if I can use ultra thin enamelled 38swg wire? I know it's thin but I need to have as thin as poss. 12 / 13.5 volts

I've searched google etc maplin, but can't figure it out.

anyone good at this sort of stuff?

 

[tim_ber]

Re: what amps allowed thro\' 38 swg ?

I mean it is 75mA thro' out total circuit

 

[halcyon]

Re: what amps allowed thro\' 38 swg ?

Depends on wire type for one thing,

Insulated Wiring Pencil Wire 38 SWG, 82 mA

Enammelled Copper wire 36 SWG 48 mA

33 SWG Enamelled copper wire, 76 mA

Brian

 

[tim_ber]

Re: what amps allowed thro\' 38 swg ?

thank you -
it is enamalled copper, so I am pushing it for sure. only 48mA as you say.

I could buy some thicker stuff, but I have a reel of 38 swg begging to be used. Would you know if I could use 2 or 3 strands twisted together to carry the same 76mA current to make everything ok?

 

[lw395]

Re: what amps allowed thro\' 38 swg ?

It depends!
Presumably for LED's voltage drop will not be the issue, so that means you are only worried about temperature rise.
The limit will depend on the ambient temp, how many wires are bundled together, safety factors and the temperature rating of the insulation.
Short wires will also lose heat through their connections.
Try www.rswww.com for data.

 

[William_H]

Re: what amps allowed thro\' 38 swg ?

Well if it is on a boat it probably won't last long with corrosion in the salty atmosphere. To my mind longer life is a good reason to use oversized wires.
olewill

 

[lw395]

Re: what amps allowed thro\' 38 swg ?

Some sympathy with that olewill, but enamel copper has the insulation bonded to the wire, so you don't get damp travelling inside it like multistrand. I try to always use decent size wire with plated strands.

 

[Ubergeekian]

Re: what amps allowed thro\' 38 swg ?

[ QUOTE ]
I need to send 75mA thro' to some leds and I am wondering if I can use ultra thin enamelled 38swg wire? I know it's thin but I need to have as thin as poss. 12 / 13.5 volts


[/ QUOTE ]
38swg is nearasdammit 1 ohm per metre. At 75mA that's a drop of 75mV/m and a power dissipation of 6mW/m. Both of these are, for all practical purposes, negligible.

 

[simonfraser]

Re: what amps allowed thro\' 38 swg ?

no prob, unless you use 10m+ of the stuff, see above !

 

[tim_ber]

Re: what amps allowed thro\' 38 swg ?

Much appreciated everyone.

It's not actually for the boat, so all is well.