BS 1363 13A Socket Continuous Max Load

sparkiemike: 
. . . At a recent Elex “seminar” Darren Staniforth from Scolmore made a comment that BS1363 socket outlets were only tested for 8A continuous load. . . 

In my previous job, we did eventually get a statement from a well known manufacturer that a 13A socket has a continuous rating of 8A. The follow up was that we changed all underfloor 13A sockets in a computer suite for 13A fused spur outlets. The downside was that the IT group could no longer disconnect or connect a rack themselves, but it did stop the issues with13A sockets under the floor failing. 

Regards,

Alan. 

Well call me insane if you want to. But. I think the “man in the street” would probably have a reasonable expectation that a 13A socket could reasonably carry a 13A load indefinately. Otherwise we`d call it a 7.3A socket - 13A max burst for 1 hour Max per 24 hour period socket or some such description. 

Personally I would not usually consider much over 10A for any time and less so with some of the carp that is readily available

AJJewsbury: 
 

It's often unclear with RCBOs whether the “type” is referring to the MCB element (B, C or D) or the RCD element (AC, A, B, K, etc) - given the usual price of B-type RCDs I might suspect in this case they're referring to the MCB element type.

   - Andy. 

I agree that some manufacturers are not clear on this. However, on this occasion, from the 1st box on the 2nd page, it is clear that it is a type B RCBO (RCD) and not a type B MCB.

Probably a cost saving exercise.

(EDIT: It goes on to say it is a Type AC RCD, imo for EV charigng type A RCD would have been better)

ebee: 
 

Well call me insane if you want to. But. I think the “man in the street” would probably have a reasonable expectation that a 13A socket could reasonably carry a 13A load indefinately. Otherwise we`d call it a 7.3A socket - 13A max burst for 1 hour Max per 24 hour period socket or some such description. 

Personally I would not usually consider much over 10A for any time and less so with some of the carp that is readily available

Couldn’t agree more, perhaps the standard needs revising.

However, on this occasion, from the 1st box on the 2nd page, it is clear that it is a type B RCBO (RCD) and not a type B MCB.

But there are no types for RCBOs - only separate types for the RCD element and the MCB element - and every RCBO has both.

  - Andy.

ebee: 
 

Well call me insane if you want to. But. I think the “man in the street” would probably have a reasonable expectation that a 13A socket could reasonably carry a 13A load indefinately. Otherwise we`d call it a 7.3A socket - 13A max burst for 1 hour Max per 24 hour period socket or some such description. 

Personally I would not usually consider much over 10A for any time and less so with some of the carp that is readily available

I agree, 13 amps should mean able to supply a nominal 13 amps continually. I would go so far as to say that a “nominal 13 amps” should mean tested at 14 amps or at 14.3 amps so as to allow for mains voltage variations and manufacturing tolerances of the connected load.

And that this should be at the highest ambient temperature likely to be encountered regularly, say 30 degrees.

A 10 amp RCBO or MCB cannot be run fully loaded at 10 amps for an extended period, it has to be derated, therefore a 10 amp EV charger needs a 16 amp protective device.

These are things you don’t find out about doing an 18th Edition Wiring Regulations training course, you actually need to do a proper electrical installation design course.

Yesterday I once again replaced a B32 MCB supplying a 8.5kW shower with a B40, because it was running permanently overloaded, I frequently see this done.

Regards that Masterplug EV socket, you will find they have a single pole B16 Type AC RCBO.

https://www.amazon.co.uk/Masterplug-Chargepoint-Charger-Charging-socket/dp/B07QB382PL

Better options are available, I would swap it out. 

But at least the socket itself complies with the regulation I posted  a picture of above as it is marked as being suitable for EV charging.

 

broadgage: 
I agree, 13 amps should mean able to supply a nominal 13 amps continually. I would go so far as to say that a “nominal 13 amps” should mean tested at 14 amps or at 14.3 amps so as to allow for mains voltage variations and manufacturing tolerances of the connected load.

And that this should be at the highest ambient temperature likely to be encountered regularly, say 30 degrees.

The copy of BS1363-2:1995 I have says the temperature rise should not be more than 52K. The connected load will be 14A for single outlets or 14A+6A for double outlets, for a minimum continuous period of 4hours or longer until stability is reached and max duration of 8hours.

I don't know where this 8A figure comes from, manufacturers should come clearn about that. Given the nature of some load on 13plugs, IMO the duration of the temperature rise should be extended in the BS 

Sparkingchip: 
 

Regards that Masterplug EV socket, you will find they have a single pole B16 Type AC RCBO.

https://www.amazon.co.uk/Masterplug-Chargepoint-Charger-Charging-socket/dp/B07QB382PL

Better options are available, I would swap it out. 

But at least the socket itself complies with the regulation I posted  a picture of above as it is marked as being suitable for EV charging.

It looks like a BG Type AC, B Curve RCBO, should could be easily swapped for a Type A, B Curve RCBO with lower current rating