advice on power supply to outbuilding

Hi looking for some advice I wont be doing any work a electrician will be .. I have a outbuilding being constructed and i will need a power supply I have asked for a quote and while looking for advice have been told that the person doing the quote cant be a qualified sparky from the advice given so here to double check

I need power running from existing consumer unit to shed. once there will need to have enough amps to run power tools/freezer and heater and lights and computer etc the sparky who will be doing me a quote says an additional consumer unit wont be needed as existing unit offers enough protection .. current CU is Wylex NM1406L 14 Way 100 Amp Double Pole Metal Consumer Unit

All metal enclosure, no plastic parts
Low Smoke and Fume Paint
Non Combustable Steel Blank plates available
Raised and removable DIN rail/Busbar assembly
Cable entry Knockouts on 5 sides Top, Bottom, Rear, left and Right
Mains Tails cable Entry Grommet available to comply with 3rd Amendment Regulations
Uo to 38 Ways Available in Mainswitch, split load, dual RCD and High Integrity
RoHS Compliant in excess of UK Standards
UKAS certified to BS EN 61439-2
Dimensions - 261mm (Height) x 343mm (Width) x 121mm (Depth)
Wylex Technical Helpline 01543 438320

other forum saying it doesnt have RCD but to me it says dual RCD.. all the MCB in it are
Wylex NHXS1B06 6 Amp 30ma Type B SPSN 1 Module RCBO ranging from 6-32amp

now the other sparkys are saying all those will be fine but if a new circuit is added it will need RCD but and i know nothing wouldnt new circuits added to free space within the box have the same protection as the rest of the other circuits?

Be easier to show a picture of this consumer unit.

westward10 said:

Be easier to show a picture of this consumer unit.

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Hi I edited and added pictures

Your circuits have RCBOs fitted so each has individual RCD protection. Any new circuit can be protected by the addition of another RCBO if the circuit requires it.

westward10 said:

Your circuits have RCBOs fitted so each has individual RCD protection. Any new circuit can be protected by the addition of another RCBO if the circuit requires it.

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Thankyou ..now to get a few more quotes as have no idea of cost involved

How far is the shed from this CU?

jobe1972 said:

existing unit offers enough protection

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It doesn't, unless you add further RCBO's which may not be necessary though(Just a MCB) depending on way your sparks decides to do the job.
There may be sufficient capacity/No of ways but it may be easier to run a single cable from CU to shed with another CU in the shed with RCBO's for power/heating/lighting etc.
If armoured it might not need RCD protection for the cable, depending upon other criteria but will do in the shed. Shed doesn't need metal, non-combustible enclosure either.

An RCD can only be omitted if ADS is satisfied without it.

DefyG said:

How far is the shed from this CU?

It doesn't, unless you add further RCBO's which may not be necessary though(Just a MCB) depending on way your sparks decides to do the job.
There may be sufficient capacity/No of ways but it may be easier to run a single cable from CU to shed with another CU in the shed with RCBO's for power/heating/lighting etc.
If armoured it doesn't need RCD protection for the cable but will do in the shed. Shed doesn't need metal, non-combustible enclosure either.

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Hi it should be around 20-22 metres from CU to where the shed will be its a concrete shed and they did say it would be armoured cable ..they did ask what would be used in there listed some stuff but I didnt know about amps etc so didnt know what was needed they said around 20 amp but looking at some of my tools that wont be enough saw alone is 8-9 amps plus a 5ft chest freezer will be in there plus computer / tv etc But as I have no idea and have to rely on advice ..The work has to be certificated and niceic if that makes much of a difference

This is a simple job, work out the design current required for the out building, run an armoured cable suitable for the job, install a new CU in the new building for the circuits required in there and add a suitable over current protective device at the house end to protect the system. A spark should do this very simply in his or her quotation, this is not a complicated job, its at school boy level, something sounds a little strange here with the comments from your sparky, are you sure you are not trying to do the job yourself?

MDJ said:

This is a simple job, work out the design current required for the out building, run an armoured cable suitable for the job, install a new CU in the new building for the circuits required in there and add a suitable over current protective device at the house end to protect the system. A spark should do this very simply in his or her quotation, this is not a complicated job, its at school boy level, something sounds a little strange here with the comments from your sparky, are you sure you are not trying to do the job yourself?

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God no when it comes to gas or electric I wouldnt even try plus I need it certificated ,,but I can only go on the words of the person who came to see me.. he pointed out that would save me some money by not having a unneeded CU in the shed but seeing how much one is for a shed around £40 doesnt seem much of a saving.. but I have no idea what the overall costs for the job

jobe1972 said:

God no when it comes to gas or electric I wouldnt even try plus I need it certificated ,,but I can only go on the words of the person who came to see me.. he pointed out that would save me some money by not having a unneeded CU in the shed but seeing how much one is for a shed around £40 doesnt seem much of a saving.. but I have no idea what the overall costs for the job

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so I assume he is installing the supply to a socket and spurring off it for the light then? from what you have said about using power tools etc I think you will need a half decent supply, still I haven;t seen the job so maybe he is right, I doubt it though

MDJ said:

so I assume he is installing the supply to a socket and spurring off it for the light then? from what you have said about using power tools etc I think you will need a half decent supply, still I haven;t seen the job so maybe he is right, I doubt it though

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He said something about a fused something as the lights hardly take anything .. I told him was mostly cordless tools so just chargers ..told him would need a heater now and then but wouldn't be on permanent .. would be a large chest freezer which he said would take 4-5 amps .. I didnt know at the time my cross saw runs at 8.3 amps so based on cordless power tools ,freezer, heater and computer he said around 20amps .. I said I would do the trench and he said that would take a chunk off as if they had to do it would be 600mm deep and if I do it its any depth I want .. I am figuring seeing the power off the saw and any other corded tools I might use 30-40 amps would be better