Adding an additional RCD to the existing consumer unit

Adam

Adam

Adam

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I’m thinking of having air con installed for the summer in my loft conversion. Due to the output of the air con unit (4.5kw) I have been told that the power cannot be taken from the existing ring main and therefore needs a new circuit from the consumer unit.

Here is the consumer unit which appears to have no space for an additional RCD.

https://imgur.com/a/d9MpTDh

Do I have any options here? I’d rather not have a whole new consumer unit added due to the cost but I may be out of luck. I notice there are 2 spaces to the left of the RCCB’s on the right which seem to be used for the lighting circuits. Could either of these be used?

I’ll be getting an electrician in to do the work but just wanted an idea of what I’m letting myself in for and if it’s worthwhile or cost effective.
 
Adam said:
I’m thinking of having air con installed for the summer in my loft conversion. Due to the output of the air con unit (4.5kw) I have been told that the power cannot be taken from the existing ring main and therefore needs a new circuit from the consumer unit.

Here is the consumer unit which appears to have no space for an additional RCD.

https://imgur.com/a/d9MpTDh

Do I have any options here? I’d rather not have a whole new consumer unit added due to the cost but I may be out of luck. I notice there are 2 spaces to the left of the RCCB’s on the right which seem to be used for the lighting circuits. Could either of these be used?

I’ll be getting an electrician in to do the work but just wanted an idea of what I’m letting myself in for and if it’s worthwhile or cost effective.
Click to expand...

Rcbo it's an rcd and an mcb in 1

But if I was the 1 carrying out the work I'd put it down for a ccu upgrade to bring it upto to current spec
 
No the are already connected to one MCB, you will need to split the tails before the CCU and add an additional CCU it does not need to be a large one a 4 or 6 way would be plenty. Or go CCU upgrade as above.
 
Check the power requirements first. A 4.5kw cooling/heating unit will draw about 1kw max as it’s c.4x efficient. I have a 4.5kw unit running off an existing ring no issues.

Unless you’re talking about a 12kw+ actual cooling power, then ignore me!
 
You can have a small separate consumer unit added if needed & it won't be expensive. Due to the location/difficulty upgrading mine, the previous occupants of my house cheaped out and had separate small ones put in for the hot tub & solar.

I'd double check the specs of the AC - suspect the cooling capacity & electrical draw are being mixed up, & you can have it off a 13a fused spur on the ring no problem.
 
Thanks for the suggestions. Looks like I have a few options.

If I am understanding this correctly, the 4.5kw unit has a maximum running current of 14.5a (https://www.airconditioningworld.co.uk/global/media/pdf/1596630956-2582.pdf).

There are 2x internal sockets on the wall where the air con would go. I'd be quite happy for the electrician to spur off the socket, add a fuse and then run the cable through the wall outside to where the air con would go. I was told by the air con installers that they would require a rotary isolator so I could still achieve this as well.

Given the 14.5a current, could a larger fused spur be used such as a 15a?
 
W
Adam said:
Thanks for the suggestions. Looks like I have a few options.

If I am understanding this correctly, the 4.5kw unit has a maximum running current of 14.5a (https://www.airconditioningworld.co.uk/global/media/pdf/1596630956-2582.pdf).

There are 2x internal sockets on the wall where the air con would go. I'd be quite happy for the electrician to spur off the socket, add a fuse and then run the cable through the wall outside to where the air con would go. I was told by the air con installers that they would require a rotary isolator so I could still achieve this as well.

Given the 14.5a current, could a larger fused spur be used such as a 15a?
Click to expand...

It will want its own dedicated 16 amp supply
 
The CU might be old, but why change if its working fine. You have 2 spare ways on the board, so you could add a RCBO and wire a new radial. Whats the cable run like? Be prepared for a heart attack when you buy the cable, copper has gone mad!

If you do go for a new CU, go for a Hagar or a Fusebox. I had 4 of each fitted recently, and the quality is well impressive, far better than the BG and contactum ones i had fitted at my parents and sisters place.

If you do go down the new CU route, get an EICR done 1st.
 
lookitsjonno said:
Do you use your Immersion heater? Couldn't you get rid of that and use the space?
Click to expand...

Thank you for the suggestion. We rarely use it so this could also be an option.

Tinders said:
The CU might be old, but why change if its working fine. You have 2 spare ways on the board, so you could add a RCBO and wire a new radial. Whats the cable run like? Be prepared for a heart attack when you buy the cable, copper has gone mad!

If you do go for a new CU, go for a Hagar or a Fusebox. I had 4 of each fitted recently, and the quality is well impressive, far better than the BG and contactum ones i had fitted at my parents and sisters place.

If you do go down the new CU route, get an EICR done 1st.
Click to expand...

It's a run up the side of the garage, in to the loft and to the other side of the house through the eaves then out the other side to where the aircon would be going. I don't think the consumer united could be any further from where the air con needs to go :)
 
Adam said:
Thanks for the suggestions. Looks like I have a few options.

If I am understanding this correctly, the 4.5kw unit has a maximum running current of 14.5a (https://www.airconditioningworld.co.uk/global/media/pdf/1596630956-2582.pdf).

There are 2x internal sockets on the wall where the air con would go. I'd be quite happy for the electrician to spur off the socket, add a fuse and then run the cable through the wall outside to where the air con would go. I was told by the air con installers that they would require a rotary isolator so I could still achieve this as well.

Given the 14.5a current, could a larger fused spur be used such as a 15a?
Click to expand...

You can't have fixed loads larger the 2kw on a ring main it needs a dedicated circuit. You will need a dedicated circuit.

If the supply to the AC is run in armoured it might not require RCD protection so easy. If it does then adding an Rcbo is the easiest way to go.

You could repurpose the Immersion breaker or possibly even replace the bus bar and move the RCD over. But I'd avoid that since the RCD is probably only designed to carry 63amps.

Have you any idea what size main fuse the property has?
 
Get a sparky or two round explain what you want and ask for some quotes, I wouldn't disconnect your immersion heater to save a couple of quid on a secondary Consumer Unit you can afford the aircon install so you can afford to get the electrics done properly.
 
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