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E.L.V. Colour Identification.

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I have just been helping a neighbour with his new camper van. Long story short, I ran a cigar lighter extension lead from the cab to the under-vehicle leisure battery. The lead originally had a male plug at one end and a female socket at the other. I cut the male plug off for a connection to the leisure battery. The flex is a white figure of 8 with one conductor marked with a black stripe. After installation I decided to double check the polarity of the socket in the cab for polarity. Low and behold the centre pin was negative and the outer ring positive, thus back to front. Why do the Chinese use black as D.C. positive indicator?

P.S. Edit. Add. I have just found this..........

DC 12v Black and White Wire (12v Wiring Color Coding Guide) (thecampingadvisor.com)

Z.

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    As mentioned in the linked text, a pairing of one 'marked' core and one plain core is normally arranged with the marked core positive, overriding any significance of the colours of the insulation and marking. My experience of figure-8 cables on DC power bricks, wall warts etc is that about 80% of manufacturers adhere to this. I have been caught out by one manufacturer that switched the marked core from negative to positive during a production run with no visible indication externally. Both versions were correctly connected to the attached coaxial DC jack so they presumably didn't see any need to warn the odd user who might need to connect directly to the cables.

    On a related note, I found one example with a really mean trick. It had a single-core screened cable (as many power bricks do) terminating in a coaxial (barrel) DC jack with centre positive. All unremarkable, until I discovered that the centre conductor of the cable was negative and connected to the outer of the jack, and the screen positive and connected to the centre contact.

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    As mentioned in the linked text, a pairing of one 'marked' core and one plain core is normally arranged with the marked core positive, overriding any significance of the colours of the insulation and marking. My experience of figure-8 cables on DC power bricks, wall warts etc is that about 80% of manufacturers adhere to this. I have been caught out by one manufacturer that switched the marked core from negative to positive during a production run with no visible indication externally. Both versions were correctly connected to the attached coaxial DC jack so they presumably didn't see any need to warn the odd user who might need to connect directly to the cables.

    On a related note, I found one example with a really mean trick. It had a single-core screened cable (as many power bricks do) terminating in a coaxial (barrel) DC jack with centre positive. All unremarkable, until I discovered that the centre conductor of the cable was negative and connected to the outer of the jack, and the screen positive and connected to the centre contact.

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Community Rules & Guidelines