MarkMc said:
ok, transistors, driven by PIC microcontroller outputs, drive 12v
through each relay primary, which then switch each of the two 240v
devices.
I think the kettle connectors are quite neat. One is the normal mains
lead in, and the two others are output types, which can be plugged in
as needed (can use one or other, or both together), and saves me having
to worry about clamping hard-wired leads in to the enclosure box.
Does that help?
Cheers,
Mark
Yup, so your main concern should be the safety aspect of the mains wiring.
Personally I would use a metal enclosure that was securely earthed by
bonding the incoming earth lead to it, using a dedicated screw with flat and
star washers. All outgoing earths would then be attached above this with
their own nut and washers. It occurs to me that by "Kettle connectors" you
mean IEC type plugs and sockets (3 small oblong pins all aligned ) whereas I
am perhaps of another older era where a "Kettle Plug" was called an
"Appliance connector" and are a lot more bulky and less reliable. I would
agree that IEC connectors would be good.
I do not have knowledge of the codes for UK wiring so hopefully others can
help you there.
You would also need to arrange for the interface wiring to seperated to
avoid potential danger should the signal wiring become connected to the
mains. A little care with wiring the relays should handle that although if
the 24vdc can be bonded to earth any mishaps should blow the fuse in the
240vac circuit. Consider the load you are supplying and if its small and the
source vac circuit has a large fuse it wouldn't be a bad idea to mebbe have
a suitable fuse mounted in the enclosure.
Perhaps another approach would be to use thyristors instead of relays but
they would definately need to be in a metal enclosure to hold down the EFI.
Best of luck with your project.