12V

IBcarguy wrote:
In trailer 12volt applications, white is positive and black negative right?

If you are talking about the leads coming off of the battery that's the way mine is wired, maybe the rest of the rig too but I haven't looked that close at it. Kind of confusing if you ask me. Now you have me thinking about it.

IBcarguy wrote:
In trailer 12volt applications, white is positive and black negative right?

No, Voltmeter is needed to test.. here is why:

In the world of Electronics, and this includes automotive world. BLACK is normally either earth ground, chassis ground or both.. Please note that this does NOT mean negative,,, it means ground (Electronics often use both PLUS and MINUS voltages In fact your desktop computer power supply has several outputs some are negative voltage)

But RV's are not wired by folks like me (Trained electronics tech) they are wired by ELECTRICANS.. The same folks who wire a sticks and bricks

And to them Black is "HOT" and White is Neutral.

On the 12 volt side of life "HOT" is Positive

So, the bottom line is without a volt meter or other polarity tester you can not be sure which is which


Suggestion... While the batteries are properly hooked up get a can of Testor's spray paint.. Red, or a bottle of red nail polish, and paint all the POSITIVE wires. All of them..

Optional ... Black on the negative wires.. but that is optional.

With RV 12vdc wiring, white is normally negative/ground and every other color is positive/hot. But you should always verify.

Test with a meter because wire colors CAN change at connectors. Never trust the codes. Someone may have screwed up.

Where automotive OEM uses B&W, white is always neg
Where automotife OEM uses Red & blk, black is always neg

Why a meter if the wire is color coded?

Black to the fuse panel fuse, white to ground. Color will not change at the connector.

Personally if pulling wire I use Red/Yellow from boating.
https://www.defender.com/pdf/abyc-wire-color-chart.pdf

vote #3 for using a meter

Use a volt meter to be sure of the polarity. In my trailer Red is hot and Black is ground from the battery to half to the electrical, the other half is White and Black.

Three things - meter, meter and meter.

In my trailer they have white and purple in some areas. Not pink or reddish, but dark shade of purple.

You really should be testing this with a volt meter. My trailer had a number of connections backwards. The QC on these RVs is not very good.