63 amp 3 phase socket protected by a 30 amp fuse RCD?

[Flanders]

Carrying out and EICR on large factory and they have welding plug into 63 amp commando sockets but are protected by 30 amp BS 88 fuses.

Now the regs states Socket outlets with a ratted current not exceeding 32 amp need RCD protection. 411.3.3 (i)

Because the Socket it 63 amp I say it does not need RCD protection because its the ratting of the socket that decides if an RCD is required ,not the over current protective device. So am not going to code this just put it as info on the observations.

Or would you guys Code it ?

Got me thinking though if you wanted to avoid fitting an RCD and don't what to do a risk assessment, just fit a 63 amp plug and socket and protected by a 16 amp MCB , Not sure how you would terminate the 1.5mm flex in the plug though

 

[Nigel]

No code. No comment.

 

[Flanders]

Just wondering why it is the ratting of the socket that is so important and not the ratting of the OCPD or have the boys and girls at the IET not thought of this ?

 

[buzzlightyear]

Just wondering why it is the ratting of the socket that is so important and not the ratting of the OCPD or have the boys and girls at the IET not thought of this ?

shhhhhh, ned ,did you know they have ears of a bat .

 

[Strima]

It does now...

 

[Flanders]

shhhhhh, ned ,did you know they have ears of a bat .

Just thought it was time for another amendment . Reg 411.3.3.1.4.6.(ii) sub section 4 All Socket outlets rated at 63amp or less should have 30ma RCD , surge protection and AFDD s

 

[Chris1234]

I’m also interested in this, we have a movable piece of equipment that is currently on a D16 with 16A MCB and 100mA RCD.
It trips the RCD (it’s in manufacturers documents that it needs a 300mA RCD).
Can I just change it to a 32A socket and remove the RCD?!

 

[Nigel]

I’m also interested in this, we have a movable piece of equipment that is currently on a D16 with 16A MCB and 100mA RCD.
It trips the RCD (it’s in manufacturers documents that it needs a 300mA RCD).
Can I just change it to a 32A socket and remove the RCD?!

Why is it on a 100mA RCD if the instructions say a 300mA is needed?

 

[Flanders]

I’m also interested in this, we have a movable piece of equipment that is currently on a D16 with 16A MCB and 100mA RCD.
It trips the RCD (it’s in manufacturers documents that it needs a 300mA RCD).
Can I just change it to a 32A socket and remove the RCD?!

No. A 32 amp socket will need a 30ma rcd protection if no risk assessment also as the manufacturers intructions say it needs a 300ma rcd then thats what you should fit, it could be triping the 100ma rcd as this is not suitable for your equipment, have you had the earth leakage tested or does it state in the intructions how much leakage there should be ?

 

[Chris1234]

It used to run fine on a 100mA RCD.
A mains filter was causing the problem, replaced it and problem went away but then came back. After speaking to manufacturer they said there can be 100mA of earth current (not that it needs 300mA, but I’ll fit one anyway).

Why does a 32A plug need an RCD, I too thought it was sockets of 16A and below?

 

[Strima]

Take a look in the 18th as it's all changed.

 

[Chris1234]

Ok, thanks.
Better get it done quick then