Double socket amps

jeallen01

Active Member
Something that no-one appears to have mentioned (and this comes from someone who was a safety standards and certification compliance engineer in the electronics and defence industries for decades)!

In general, the wattage (&/or voltage and current) markings on the majority of electrical equipment and appliances (sometimes by a large amount!) overstate their actual power-draw requirements - in fact it's almost "mandatory" because the safety standards require that the marked ratings must not understate the power draw, but there is no requirement that they can't overstate it! (many companies for which I worked, and my own approach, took advantage of that "lack of clarity", "just to be safe")!

Therefore most manufacturers do "play safe" and overstate it, often by a large margin - if you are really worried, then get a plug-in power meter and measure how much power each appliance actually draws!
 
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jeallen01

Active Member
Post deleted - due "confusion" on my part as to which post I thought I should be referrencing :facepalm:
 
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Cocksure

Distinguished Member
Therefore most manufacturers do "play safe" and overstate it, often by a large margin - if you are really worried, then get a plug-in power meter and measure how much power each appliance actually draws!
Now that does explain a few things :)
I haven’t come across a true 10.5kw shower in years!

On the plus side I’m fitting an 11.5 kw electric boiler this week and the largest rcbo i can find is a 45a, sparki did suggest I try a C rated but haven’t been able to find one of those. Hopefully I’ll just be ok now (its 245 volts at the property, still slightly over though)
 
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ufo550

Well-known Member
There are some manufacturers who make 50A RCBO’s. Do you have an existing CU, or will it be a new one being installed. You could have a small CU for just the boiler.

You may not be able to use a C type, as it might not achieve the required disconnection time, with the Zs of the circuit.
 

Cocksure

Distinguished Member
There are some manufacturers who make 50A RCBO’s. Do you have an existing CU, or will it be a new one being installed. You could have a small CU for just the boiler.

You may not be able to use a C type, as it might not achieve the required disconnection time, with the Zs of the circuit.
Highest I’ve found so far has been from Hager or protec and they cut off at 45a. Rung a couple of electrical merchants and none of them know anybody who makes a larger.

At the moment its an niglon DB which are frankly... the fail rate is too high. What I was hoping to do was find a 50amp rcbo then change the board over to that make and put the current niglon rcbo’s into stock (got loads of niglon boards).

Realistically I can see me needing to add a new sub Distribution board just for the boiler as 50a mcb’s are easy to get hold of. Main boards are always rcbo’s as whilst there expensive the time they save fault finding or maintenance makes them worth every penny.

I get my work checked/tested by a sparki after i do it, not that daft :laugh:
 

ufo550

Well-known Member
It will depend on the installation method for the supply for you electric boiler, as to whether it needs additional protection (RCD) or not.

Hager is a good manufacturer. I would involve your electrician early on in the design stage, before you make such decisions.
 

Cocksure

Distinguished Member
I did :) he was the one who recommended the type C, trouble is that is even harder to find :(

Don’t know if it legal needs to be rcb protect, but as it’s going into a rental property, I always play on the safe side. Boards don’t legal need to be changed to the latest edition (18 part 3???) still happening mind:laugh:
 

ufo550

Well-known Member
Type C are for use with motors etc, to combat the surge when starting up. Using type C because you can't find a type B, is not really a good design; there are quite a few type B RCBO's.

Doesn't matter if its rental or not, the requirement for additional protection, depends on installation method and or circuit use.

If your struggling to find a device for you existing consumer unit, it might be easier to install a small single use consumer unit, comprising of an RCD & separate 50A MCB etc. This would need to comply with the latest wiring regs, as would the existing earthing & bonding.

If its a rental property, it now may require an EICR.
 

Cocksure

Distinguished Member
Already in hand 🙂 I’m going to finish off fitting the boiler and the sparki will check my work and then do an EICR. I did wonder about the type C, but as the sparki suggested it to begin with...

odds are it will end up being done as you suggest 👍. Plumbing side is done now, so next week is wiring, controls etc
 

ufo550

Well-known Member
Already in hand 🙂 I’m going to finish off fitting the boiler and the sparki will check my work and then do an EICR. I did wonder about the type C, but as the sparki suggested it to begin with...

odds are it will end up being done as you suggest 👍. Plumbing side is done now, so next week is wiring, controls etc
Be mindful in domestic dwellings replacement Consumer Units and new circuits (England & Wales)are notifiable to your LBC. Part P document gives guidance on how that can be achieved. An EICR is not meant for new works, and is not one of those methods as described in Part P. An Electrical Installation Condition Report (EICR), is an opinion of the condition of an existing installation. The certificate provides no documentation of the design, installation, inspection & testing of new works. If there was an insurance claim, you would not be able to prove the new installation was safe to use at the time it was put into service.

That said, it seems some LBC's are confused with the process. Up until two years ago, I was registered with a Scheme, carrying out such works. I will need to replace my CU etc shortly in my own house. I was asked to send in my last Scheme Assessment, to my LBC. After some debate, they said I could carry out my own works, but would it need to be tested by another sparks, with an EICR completed. Which is nonsense.

I've read about others, who have done what you are doing, but their LBC wanted an EIC. I would ask your LBC for guidance.
 

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