What do you think about a 16A socket on a 20A breaker

[bill01803]

Been asked to provide a 4 pole 16A socket with RCD protection with a C20 protecting the circuit specified by the manufacture of the machine, should I not use a 32A socket?

 

[telectrix]

can't see a problem as long as the socket is dedicated to that particular machine and it does not draw >16A ( excepting start up).

 

[James]

I have come across this a few times.
It’s normally because people have had trouble with inrush currents for fork lift chargers.

My answer is normally
No I won’t do a 16A socket on a 20A ocd.
You can often provide 16A D type breaker instead
Or a 20A fixed connection.
[automerge]1601289951[/automerge]

can't see a problem as long as the socket is dedicated to that particular machine and it does not draw >16A ( excepting start up).

How do you dedicate a socket to a particular machine?
In my experience, people will plug in what they want, where they want. Ignoring any labels or warnings if you put any up.

 

[Pretty Mouth]

Appears to be ok according to the OSG, p190:

H3
Radial final circuits using 16 A socket-outlets complying with 85 EN 60309-2 (85 4343)

H3.1
General
Where a radial circuit feeds equipment the maximum demand of which, having allowed for diversity, is known or estimated not to exceed the rating of the overcurrent protective device and in any event does not exceed 20 A, the number of socket-outlets is unlimited.

H3.1
Circuit protection
The overcurrent protective device should have a rating not exceeding 20 A.

 

[Dustydazzler]

Personally no issue with that parti set up , as already mentioned a 16a D type is possibly a better solution

 

[telectrix]

Personally no issue with that parti set up , as already mentioned a 16a D type is possibly a better solution

not if the Zs is > Zsmax. for a 16A type D.

 

[Dustydazzler]

not if the Zs is > Zsmax. for a 16A type D.

yes must check the max permitted Zs in the old OSG

 

[telectrix]

it's about 0.7 (without Ci and the 0.8 temp. correction ).

 

[Dustydazzler]

it's about 0.7 (without Ci and the 0.8 temp. correction ).

quite achievable on 4mm cable unless it’s a very long cable run ...

 

[Rockingit]

Except..... can't recall the reg number off the top of my head but ALL components in a chain require a rating to a minimum of the CPD, so in this case the 16a socket would need to have a rating of 20a minimum, which clearly it doesn't.
I came up on this issue on a scheme inspection years ago when I'd used a 10a rated switch that was switching something like 40w but it was being fed ultimately from a 13a fused outlet upstream that split.

 

[ruston]

Except..... can't recall the reg number off the top of my head but ALL components in a chain require a rating to a minimum of the CPD, so in this case the 16a socket would need to have a rating of 20a minimum, which clearly it doesn't.
I came up on this issue on a scheme inspection years ago when I'd used a 10a rated switch that was switching something like 40w but it was being fed ultimately from a 13a fused outlet upstream that split.

Sorry for the grotty picture , but is this the reg you had in mind?

 

[Rockingit]

Sorry for the grotty picture , but is this the reg you had in mind?View attachment 61079

That's the one. 512.1.2

 

[bill01803]

32A sockets it is then

 

[Rockingit]

Or see if you've the Zs to fit a D type 16A (would be quicker and cheaper!)

 

[snowhead]

32A sockets it is then

Only providing the whole circuit is rated for 32amp, otherwise if an appliance rated at 32amp with a 32amp plug is plugged in the 20a mcb will trip.