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MarkMc
Guest
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 Posted:
Thu Mar 03, 2005 8:01 pm Post subject:
240 vac Relay cct |
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Hi
I'm putting together a cct which will takes a 240vac input and switches
it via 2 relays to two 24v ac outputs.
Currently I'm enclosing this cct inside a plastic box. The 240vac
inputs are via kettle lead connectors in and out. Should I be
enclosing this inside a metal box instead?
I'm in the UK, is there any legal stuff I should be aware of for
240vac?
Cheers,
Mark
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Rheilly Phoull
Guest
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| Posted:
Fri Mar 04, 2005 6:10 am Post subject:
Re: 240 vac Relay cct |
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"MarkMc" <mark.mcgee@csfb.com> wrote in message
news:1109856898.820359.237870@o13g2000cwo.googlegroups.com...
| Quote: | Hi
I'm putting together a cct which will takes a 240vac input and switches
it via 2 relays to two 24v ac outputs.
Currently I'm enclosing this cct inside a plastic box. The 240vac
inputs are via kettle lead connectors in and out. Should I be
enclosing this inside a metal box instead?
I'm in the UK, is there any legal stuff I should be aware of for
240vac?
Cheers,
Mark
|
Perhaps a tad more info on the cicuit ?
I.e two 240vac coil relays switching 24v or a 240 to 24 tranny that feeds
the relays which are switched externally etc etc.
Pretty hard to help without more details although the "kettle" connectors
doesnt sound really "pretty" :-)
--
Regards ..... Rheilly Phoull |
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MarkMc
Guest
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| Posted:
Fri Mar 04, 2005 4:13 pm Post subject:
Re: 240 vac Relay cct |
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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
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Rheilly Phoull
Guest
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| Posted:
Sat Mar 05, 2005 6:10 am Post subject:
Re: 240 vac Relay cct |
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"MarkMc" <mark.mcgee@csfb.com> wrote in message
news:1109931203.857353.103950@l41g2000cwc.googlegroups.com...
| Quote: | 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.
--
Regards ..... Rheilly Phoull |
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MarkMc
Guest
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| Posted:
Mon Mar 07, 2005 7:09 pm Post subject:
Re: 240 vac Relay cct |
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Thanks for the advice.
I'll go for a metal enclosure, with the earth leads connected. I'll
have to think of a way to segregate the user switches and buttons so
that they can't get touched by any loose mains leads.
btw. IEC type plugs and sockets is correct.
Cheers,
Mark |
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Rich Grise
Guest
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| Posted:
Tue Mar 08, 2005 4:55 am Post subject:
Re: 240 vac Relay cct |
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On Mon, 07 Mar 2005 05:09:12 -0800, MarkMc wrote:
| Quote: | Thanks for the advice.
I'll go for a metal enclosure, with the earth leads connected. I'll
have to think of a way to segregate the user switches and buttons so
that they can't get touched by any loose mains leads.
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You mount them in such a fashion that the operator-accessible bits (switch
handles, button buttons) are on the outside of the panel, and the electric
bits (terminals, wires, etc) are on the inside.
Good Luck!
Rich |
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