Automotive wire size

[Chris Adams]

Hello,
I have a '91 Toyota Corolla. I have recently replaced the wires on
the licence plate lights (in the back). The original wires
don't have any size markings, they could be either #18 or #20.
I used #20 wire as replacement.
My question is: if the original size is #18, is it ok to use
#20 as its replacement? The lightbulbs are 12V mini lightbulb.

Thanks!

 

[maxfoo]

Hello,
I have a '91 Toyota Corolla. I have recently replaced the wires on
the licence plate lights (in the back). The original wires
don't have any size markings, they could be either #18 or #20.
I used #20 wire as replacement.
My question is: if the original size is #18, is it ok to use
#20 as its replacement? The lightbulbs are 12V mini lightbulb.

Thanks!

does the bulb draw more than 11 amps???

Load Carrying Capacities (see table below)

http://www.powerstream.com/Wire_Size.htm















Remove "HeadFromButt", before replying by email.

 

[James Sweet]

does the bulb draw more than 11 amps???

Load Carrying Capacities (see table below)

http://www.powerstream.com/Wire_Size.htm

That doesn't really apply to automotive, for an 11A load you'd want at least
#14, but #12 would be better depending on the length of the run. At 12v the
voltage drop over the wire becomes much more important.

If the bulbs are bright enough then your #20 will be fine, I would guess
they don't even draw an amp between them.

 

[Daniel J. Stern]

That doesn't really apply to automotive

Very correct, it doesn't. A lot of people -- including some of the
beancounters at some of the automakers -- use tables like this to figure
out "acceptable" wire sizes, with yucky results.

If the bulbs are bright enough then your #20 will be fine, I would guess
they don't even draw an amp between them.

They're 3, 4 or 5w items, so a max of 10w at 12v, so yeah, less than an
amp max. That said, #20 is generally NOT used in automotive service for
mechanical-weakness reasons. #18 is regarded as the minimum acceptable
gauge, even where #20 would be electrically acceptable.

-Stern