I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Can you not use a bell transformer? Eg

https://www.tlc-direct.co.uk/Products/TCTR7.html

--
Robin
reply-to address is (intended to be) valid

On 02/01/2018 23:17, Robin wrote:
On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal
fuses in both L and N) was wired into the lighting circuit. It would
be very difficult to get non-lighting power to this location (near the
ceiling, in the kitchen), I don't have space for a fused spur and I
can't find a 13A socket with a built-in fuse. I'm planning on using a
standard 13A socket, fitting an internal 500mA in-line fuse and adding
a suitable label to the socket.
What does the jury think?

Can you not use a bell transformer? Eg

https://www.tlc-direct.co.uk/Products/TCTR7.html

I could, but I've already got a suitable wallwart

Have you tested said wart does the job adequately? I've no idea of the load
but if its got any inductance in it then they don't like that very much.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On 02/01/2018 23:17, Robin wrote:
On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Can you not use a bell transformer? Eg

https://www.tlc-direct.co.uk/Products/TCTR7.html

I could, but I've already got a suitable wallwart

On 03/01/2018 09:59, Brian Gaff wrote:
Have you tested said wart does the job adequately? I've no idea of the load
but if its got any inductance in it then they don't like that very much.
Brian


It's fine with a big capacitor across the output.

On Wednesday, 3 January 2018 12:18:19 UTC, wrote:
On 03/01/2018 09:59, Brian Gaff wrote:
Have you tested said wart does the job adequately? I've no idea of the load
but if its got any inductance in it then they don't like that very much.
Brian


It's fine with a big capacitor across the output.

yes, done that before. A switched mode wart would get rid of the wasted 2 watts.


NT

In article ,
wrote:
On 02/01/2018 23:17, Robin wrote:
On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal
fuses in both L and N) was wired into the lighting circuit. It would
be very difficult to get non-lighting power to this location (near the
ceiling, in the kitchen), I don't have space for a fused spur and I
can't find a 13A socket with a built-in fuse. I'm planning on using a
standard 13A socket, fitting an internal 500mA in-line fuse and adding
a suitable label to the socket.
What does the jury think?

Can you not use a bell transformer? Eg

https://www.tlc-direct.co.uk/Products/TCTR7.html

I could, but I've already got a suitable wallwart

Are you sure it is up to the job? Most bell transformers are bigger than
wall warts.
Since you already have the wiring in place for a proper bell transformer,
why not just replace it?

--
*Why is a boxing ring square?

Dave Plowman London SW
To e-mail, change noise into sound.

On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

won't be a problem. But any mains fuse below 3A does fail in time.


NT

On 03/01/2018 00:46, wrote:

But any mains fuse below 3A does fail in time.


NT


Not when the load is constant and small. I fitted 2A or 3A fuses at
every one of the thousands of TV distribution head-ends and repeaters I
built between 1975 and 2015 and there was no problem with spurious fuse
breaks.

Bill

On Wed, 03 Jan 2018 01:38:36 +0000, Bill Wright wrote:

On 03/01/2018 00:46, wrote:

But any mains fuse below 3A does fail in time.


NT


Not when the load is constant and small. I fitted 2A or 3A fuses at
every one of the thousands of TV distribution head-ends and repeaters I
built between 1975 and 2015 and there was no problem with spurious fuse
breaks.

Our 34 year old central heating system is still on its original 3A fuse
and I have a reasonable expectation that the fuse will outlive the boiler
even if it lasts another 16 years or more (assuming the system doesn't
suffer an electrical fault in the meantime).

--
Johnny B Good

On Wednesday, 3 January 2018 01:38:39 UTC, Bill Wright wrote:
On 03/01/2018 00:46, tabbypurr wrote:

But any mains fuse below 3A does fail in time.

Not when the load is constant and small. I fitted 2A or 3A fuses at
every one of the thousands of TV distribution head-ends and repeaters I
built between 1975 and 2015 and there was no problem with spurious fuse
breaks.

Bill

I fitted many 2A fuse years ago with tiny loads and many eventually failed. But not thousands. Perhaps they weren't as good quality as they appeared.


NT

On 03/01/2018 06:21, wrote:
On Wednesday, 3 January 2018 01:38:39 UTC, Bill Wright wrote:
On 03/01/2018 00:46, tabbypurr wrote:

But any mains fuse below 3A does fail in time.

Not when the load is constant and small. I fitted 2A or 3A fuses at
every one of the thousands of TV distribution head-ends and repeaters I
built between 1975 and 2015 and there was no problem with spurious fuse
breaks.

Bill

I fitted many 2A fuse years ago with tiny loads and many eventually failed. But not thousands. Perhaps they weren't as good quality as they appeared.


Quick blow fuses often fail due to transients. Usually not fast enough
to protect the equipment though!

Bill

In article ,
says...


Quick blow fuses often fail due to transients. Usually not fast enough
to protect the equipment though!


Yes - semiconductors self destruct faster than fuses!

I don't ever recall problems with valved equipment protected
by quick blow fuses, though.


--

Terry

---
This email has been checked for viruses by AVG.
http://www.avg.com

I'm always finding fuses of many sizes in plugs stopping working recently
after about 10 years. the all just fell to bits in that the wire inside came
off the end.

Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

won't be a problem. But any mains fuse below 3A does fail in time.


NT

In article ,
"Brian Gaff" writes:
I'm always finding fuses of many sizes in plugs stopping working recently
after about 10 years. the all just fell to bits in that the wire inside came
off the end.

I do see some old fuses at repair events which are not labelled
as BS1362. I have one which failed to interrupt the supply when
it blew and turned into an arc lamp inside the plug. There was
no evidence it was sand filled, so failing to break the circuit
is not unexpected.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

expressed precisely :
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

won't be a problem. But any mains fuse below 3A does fail in time.


NT

Fuses range in value from ratings of 1,000's of amps, down to just a
few milliamps in equipment fuses. They only tend to blow when subjected
to either a fault load or a regular surge load.

On Wednesday, 3 January 2018 10:37:47 UTC, Harry Bloomfield wrote:
tabbypurr expressed precisely :
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:

I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

won't be a problem. But any mains fuse below 3A does fail in time.


NT

Fuses range in value from ratings of 1,000's of amps, down to just a
few milliamps in equipment fuses. They only tend to blow when subjected
to either a fault load or a regular surge load.

by definition they don't 'blow' when they break, they just break.

On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Your door bell system with transformer uses a lot of energy.
Low power but on all the time.
Consider getting a (wireless) battery replacement.

On Wednesday, 3 January 2018 07:17:10 UTC, harry wrote:
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Your door bell system with transformer uses a lot of energy.

nonsense

Low power but on all the time.
Consider getting a (wireless) battery replacement.

unwise

On 03/01/2018 08:17, wrote:
On Wednesday, 3 January 2018 07:17:10 UTC, harry wrote:
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Your door bell system with transformer uses a lot of energy.

How many batteries can you buy with say a years worth at a 10W load?

nonsense

Low power but on all the time.
Consider getting a (wireless) battery replacement.

unwise

Maybe, you can have wired battery powered door bells.

On Wednesday, 3 January 2018 21:28:19 UTC, Fredxx wrote:
On 03/01/2018 08:17, tabbypurr wrote:
On Wednesday, 3 January 2018 07:17:10 UTC, harry wrote:
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:

I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Your door bell system with transformer uses a lot of energy.

How many batteries can you buy with say a years worth at a 10W load?

No newish wallwart quiesces at anywhere near 10W. Not even 1W now.
1W is about £1 a year, for which you can get a poundland pack of junk batteries or a few good ones.

The batteries are probably slightly cheaper if using electronic sounders, but you have to buy & replace them every so often, you'l get missed calls and the battery contacts will corrode sooner or later. In short it's a false economy, if it's an economy at all.


Consider getting a (wireless) battery replacement.

unwise

Maybe, you can have wired battery powered door bells.

Yes - the worst of both worlds.


NT

On 03/01/2018 22:51, wrote:
On Wednesday, 3 January 2018 21:28:19 UTC, Fredxx wrote:
On 03/01/2018 08:17, tabbypurr wrote:
On Wednesday, 3 January 2018 07:17:10 UTC, harry wrote:
On Tuesday, 2 January 2018 23:10:04 UTC, wrote:

I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Your door bell system with transformer uses a lot of energy.

How many batteries can you buy with say a years worth at a 10W load?

No newish wallwart quiesces at anywhere near 10W. Not even 1W now.
1W is about £1 a year, for which you can get a poundland pack of junk batteries or a few good ones.

The batteries are probably slightly cheaper if using electronic sounders, but you have to buy & replace them every so often, you'l get missed calls and the battery contacts will corrode sooner or later. In short it's a false economy, if it's an economy at all.


Consider getting a (wireless) battery replacement.

unwise

Maybe, you can have wired battery powered door bells.

Yes - the worst of both worlds.


NT

How do you make that out? I have a wired battery bell (two bells in
parallel actually), and don't have to change the alkaline C cells any
more often than their shelf life of 6 years.
--
Dave W

In article 5826c7ec-ce64-4df5-9a2f-
, says...

1W is about £1 a year, for which you can get a poundland
pack of junk batteries or a few good ones.


What makes you think that Poundland batteries are junk?

I've been using their Kodak Extralife batteries for years -
long life and never had one leak.

Those currently on sale have a shelflife of ten years. The
only downside is that I noticed last week that you only get 5
for a £1 now - before it was 6. However, everywhere else I've
seen them there have never been more than 4 in a pack.

Running costs are less than a third of the costs of the
cheapest Duracell - see the results he

http://www.batteryshowdown.com/


--

Terry

---
This email has been checked for viruses by AVG.
http://www.avg.com

In article ,
harry wrote:
Your door bell system with transformer uses a lot of energy.
Low power but on all the time.

And you think battery costs will be less?

Consider getting a (wireless) battery replacement.

Which ain't going to last 80 years. ;-)

--
*Taxation WITH representation ain't much fun, either.

Dave Plowman London SW
To e-mail, change noise into sound.

On Wednesday, 3 January 2018 11:17:35 UTC, Dave Plowman (News) wrote:
In article ,
harry wrote:
Your door bell system with transformer uses a lot of energy.
Low power but on all the time.

And you think battery costs will be less?

The battery is only in use for a few seconds each week.
The transformer is continually drawing current

In article ,
harry wrote:
On Wednesday, 3 January 2018 11:17:35 UTC, Dave Plowman (News) wrote:
In article ,
harry wrote:
Your door bell system with transformer uses a lot of energy.
Low power but on all the time.

And you think battery costs will be less?

The battery is only in use for a few seconds each week.
The transformer is continually drawing current

And how much current do you think it draws?

--
*Everybody lies, but it doesn't matter since nobody listens*

Dave Plowman London SW
To e-mail, change noise into sound.

On Thursday, 4 January 2018 11:42:17 UTC, Dave Plowman (News) wrote:
In article ,
harry wrote:
On Wednesday, 3 January 2018 11:17:35 UTC, Dave Plowman (News) wrote:
In article ,
harry wrote:
Your door bell system with transformer uses a lot of energy.
Low power but on all the time.

And you think battery costs will be less?

The battery is only in use for a few seconds each week.
The transformer is continually drawing current

And how much current do you think it draws?

the battery or the transformer, how about both

On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Nothing wrong with it in principle. A 3A fuse would probably be more
useful.

You could also look at 2A plugs/sockets if you can't find a
PSU/transformer that can be wired directly. e.g:

https://www.tlc-direct.co.uk/Products/CB7046.html

Having said that, you can get neat bell transformers that can be wired
directly. What is it to power? Do you need DC or is AC ok?

--
Cheers,

John.

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

On 03/01/2018 08:35, John Rumm wrote:
On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Nothing wrong with it in principle. A 3A fuse would probably be more
useful.

You could also look at 2A plugs/sockets if you can't find a
PSU/transformer that can be wired directly. e.g:

https://www.tlc-direct.co.uk/Products/CB7046.html

Having said that, you can get neat bell transformers that can be wired
directly. What is it to power? Do you need DC or is AC ok?


It's for a servant call board, almost identical to this:
https://www.youtube.com/watch?v=VNZxBMfUmZ8. There's also a repeater
bell at the far end of the house.

It was running, very feebly, on AC. I experimented with a bench supply
and found that it's much happier with about 5V DC so found a 5V wart in
a box and added a 470uF cap inside the indicator box. The socket needs
to be 13A because of the wart plug.

On Wednesday, 3 January 2018 12:30:33 UTC, wrote:
On 03/01/2018 08:35, John Rumm wrote:
On 02/01/2018 23:10, wrote:

I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Nothing wrong with it in principle. A 3A fuse would probably be more
useful.

You could also look at 2A plugs/sockets if you can't find a
PSU/transformer that can be wired directly. e.g:

https://www.tlc-direct.co.uk/Products/CB7046.html

Having said that, you can get neat bell transformers that can be wired
directly. What is it to power? Do you need DC or is AC ok?


It's for a servant call board, almost identical to this:
https://www.youtube.com/watch?v=VNZxBMfUmZ8. There's also a repeater
bell at the far end of the house.

It was running, very feebly, on AC. I experimented with a bench supply
and found that it's much happier with about 5V DC so found a 5V wart in
a box and added a 470uF cap inside the indicator box. The socket needs
to be 13A because of the wart plug.

I got better results with several thousand uF at the PSU end of the wire before the switch. Electromagnetic movements benefit from a good kick. That was running an old mercury switch dingdong.


NT

On 03/01/2018 19:42, wrote:
On Wednesday, 3 January 2018 12:30:33 UTC, wrote:
On 03/01/2018 08:35, John Rumm wrote:
On 02/01/2018 23:10, wrote:

I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?

Nothing wrong with it in principle. A 3A fuse would probably be more
useful.

You could also look at 2A plugs/sockets if you can't find a
PSU/transformer that can be wired directly. e.g:

https://www.tlc-direct.co.uk/Products/CB7046.html

Having said that, you can get neat bell transformers that can be wired
directly. What is it to power? Do you need DC or is AC ok?


It's for a servant call board, almost identical to this:
https://www.youtube.com/watch?v=VNZxBMfUmZ8. There's also a repeater
bell at the far end of the house.

It was running, very feebly, on AC. I experimented with a bench supply
and found that it's much happier with about 5V DC so found a 5V wart in
a box and added a 470uF cap inside the indicator box. The socket needs
to be 13A because of the wart plug.

I got better results with several thousand uF at the PSU end of the wire before the switch. Electromagnetic movements benefit from a good kick. That was running an old mercury switch dingdong.


NT

I didn't explain that well. The cap is inside the box but across the
output of the wart, if it was across the bell it would make things worse.

On Wed, 3 Jan 2018 19:53:01 +0000, wrote:

I didn't explain that well.

Well, try something new

Crank Doorbell Circuit Schematic

http://www.electroschematics.com/6304/crank-doorbell/

On 03/01/2018 12:30, wrote:
It's for a servant call board, almost identical to this:
https://www.youtube.com/watch?v=VNZxBMfUmZ8. There's also a repeater
bell at the far end of the house.

Wife or kids ?. don't people just their phones or tablets
these days ?.

On 06/01/2018 20:02, Andrew wrote:
On 03/01/2018 12:30, wrote:
It's for a servant call board, almost identical to this:
https://www.youtube.com/watch?v=VNZxBMfUmZ8. There's also a repeater
bell at the far end of the house.

Wife or kids ?. don't people just their phones or tablets
these days ?.
:-) In this case its name is different to its purpose

On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?


Why would you want a non lighting power source?

Why would you want a socket with a 3A fuse in it if the wallwart is
designed to fit a 13A socket?

Am I just missing something?

Why not just fit a 13A socket from the existing power supply, plug your
wallwart into that and be done with it?



--
Adam

ARW wrote:

On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal fuses
in both L and N) was wired into the lighting circuit. It would be very
difficult to get non-lighting power to this location (near the ceiling,
in the kitchen), I don't have space for a fused spur and I can't find a
13A socket with a built-in fuse. I'm planning on using a standard 13A
socket, fitting an internal 500mA in-line fuse and adding a suitable
label to the socket.
What does the jury think?


Why would you want a non lighting power source?

Why would you want a socket with a 3A fuse in it if the wallwart is
designed to fit a 13A socket?

Am I just missing something?

Why not just fit a 13A socket from the existing power supply, plug your
wallwart into that and be done with it?

I agree. The wiring to the socket is protected by the MCB and it is the
wall wart's job (if even vaguely reputable) to protect its own 240V
components as well as the ElV side.

--

Roger Hayter

On 03/01/2018 20:30, ARW wrote:
On 02/01/2018 23:10, wrote:
I need to replace an ancient bell/call box power supply with a modern
wallwart. The original transformer (from the 1930s, with internal
fuses in both L and N) was wired into the lighting circuit. It would
be very difficult to get non-lighting power to this location (near the
ceiling, in the kitchen), I don't have space for a fused spur and I
can't find a 13A socket with a built-in fuse. I'm planning on using a
standard 13A socket, fitting an internal 500mA in-line fuse and adding
a suitable label to the socket.
What does the jury think?


Why would you want a non lighting power source?

Why would you want a socket with a 3A fuse in it if the wallwart is
designed to fit a 13A socket?

Am I just missing something?

Why not just fit a 13A socket from the existing power supply, plug your
wallwart into that and be done with it?


Well done that man! I'd assumed that having a 13A socket on the lighting
circuit was against some regulation (that I hadn't found) and failed to
engage brain. Thanks! Brain now engaged and I will stop thinking about
it (but I *will* add a label to the socket, for the benefit of whoever
is here next).

On 04/01/2018 00:01, wrote:
On 03/01/2018 20:30, ARW wrote:

Why not just fit a 13A socket from the existing power supply, plug
your wallwart into that and be done with it?


Well done that man! I'd assumed that having a 13A socket on the lighting
circuit was against some regulation (that I hadn't found) and failed to
engage brain. Thanks! Brain now engaged and I will stop thinking about
it (but I *will* add a label to the socket, for the benefit of whoever
is here next).

Having 13A socket on a lighting circuit is fine as long as it is not
going to be mistaken for a general purpose socket. An additional label
on the socket also helps.

I doubt that anyone is going to climb up and use your doorbell socket to
plug a toaster in:-)


--


Adam

On Thursday, 4 January 2018 18:59:33 UTC, ARW wrote:
On 04/01/2018 00:01, wrote:
On 03/01/2018 20:30, ARW wrote:

Why not just fit a 13A socket from the existing power supply, plug
your wallwart into that and be done with it?


Well done that man! I'd assumed that having a 13A socket on the lighting
circuit was against some regulation (that I hadn't found) and failed to
engage brain. Thanks! Brain now engaged and I will stop thinking about
it (but I *will* add a label to the socket, for the benefit of whoever
is here next).

Having 13A socket on a lighting circuit is fine as long as it is not
going to be mistaken for a general purpose socket. An additional label
on the socket also helps.

I doubt that anyone is going to climb up and use your doorbell socket to
plug a toaster in:-)


Oh come on I'm sure some of us work with studenys, apprentices, YTS or whatever the lastest term is.

Monkey dust :- Kelly work experience
https://www.youtube.com/watch?v=ERmdTGJxIhg

On 04/01/2018 18:59, ARW wrote:
On 04/01/2018 00:01, wrote:
On 03/01/2018 20:30, ARW wrote:

Why not just fit a 13A socket from the existing power supply, plug
your wallwart into that and be done with it?


Well done that man! I'd assumed that having a 13A socket on the
lighting circuit was against some regulation (that I hadn't found) and
failed to engage brain. Thanks! Brain now engaged and I will stop
thinking about it (but I *will* add a label to the socket, for the
benefit of whoever is here next).

Having 13A socket on a lighting circuit is fine as long as it is not
going to be mistaken for a general purpose socket. An additional label
on the socket also helps.

I doubt that anyone is going to climb up and use your doorbell socket to
plug a toaster in:-)


--


Adam
Do US or continental wall warts plug into 5 amp round pin sockets
intended for lighting ?.