On 30/08/2013 16:52, Rick Hughes wrote:
My neighbour ... again.

He has a 3ph supply, meter feeding a TPN switch fuse.
1ph feeding house, from this he wants to allow for fact that he will be
connecting a 3ph lathe in the future.
I have recommended a further TPN switch fuse downstream from his
existing one, fused to suit Lathe.

He asked me is there a requirement to have RCD protection for a lathe
....... the last time I worked on lathe installs, there was no such
requirement - that was on an Engineering workshop in early 80's
60+ machines, none on any RCCD (or ELCB at that time)

Any requirement for RCD protection would apply to the cable rather than
the machine as such. So if surface wired, or in trunking, or one of the
approved shielded cable types (SWA etc) then there would be no specific
requirement for a RCD to protect the cable.

Is there a requirement for RCCD protection on a fixed 3ph machine ?
Interested to know if there is a requirement for earth fault protection.

I would expect a lather to be a class I device (i.e. must be earthed)

However fixed equipment of that nature is less of a shock risk than
portable kit you drag about trailing a flex. Keep in mind it might have
cooling / cutting lubricant pumps etc, so you have water and electricity
in close proximity.

He also had in his hand a 3ph RCCB .... asking if he could fit that ...
my understanding is, 'yes' downstream of TPN switch fuse it will provide
earth trip protection, but no overload protection (fuses in TPN switch
fuse supply that)

Yup.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/