RE: Re: CBus introductory course

["Keith Doxey" <ukha@xxxxxxx>]

36V DC would not be a problem as Telephone lines are nominally 50V but can
be as high as 70V or 80V for digital lines and Telex.

Power Over Ethernet (POE) is also around 48V. That carried Data and Power
in
the same cable.

Keith

www.diyha.co.uk
www.kat5.tv


> -----Original Message-----
> From: Paul Robinson [mailto:ukcueman@xxxxxxx]
> Sent: 16 June 2003 16:38
> To: ukha_d@xxxxxxx
> Subject: Re: [ukha_d] Re: CBus introductory course
>
>
> Hi Rob,
>
> Apart from the qusetion of whether it would work, it was also
> suggested to
> me that the regulations require physical separation between
> cables that
> carry power from those that don't, even if they only carry
> DC. For those
> that are not familiar with this, cbus cat5 carries 15-36V DC to power
> devices. So it's possible that laying cbus cat5 next to other
> cat5 breaches
> the regs.
>
> I don't have a copy of the regs themselves, but I do have a
> copy of "The
> electrician's guide to the 16th edition of the IEE wiring
> regulations" by
> John Whitfield. Unfortunately, it isn't explicit on this
> matter. The closest
> relevant info I can find is that to be considered an SELV
> system, "there
> must be physical separation from the conductors of other
> systems...". So
> it's possible that an incorrectly installed CBus system does
> not meet the
> requirements of an SELV system.
>
> I don't know what the consequences of that are, nor whether
> the regs are
> really able to cope with this.
>
> Paul