I went round a friends house the other day to change a few lights, when I got there he showed me he'd had his CCU changed as i'd advised him to a few times. Anyway when I went to switch off the upstairs lights, I noticed it was an MK split load board but with no 100A Main Switch, just two 80A rated RCD's. They also hadn't fitted another main switch anywhere near the board, I'm pretty sure that's not allowed, I always thought you had to have a Main Switch as well as the RCD's?
RCD's Used as Main Switches
- Thread starter Keith1978
- Start date
Sponsored Links
What is the supply type?
are the two rcds are connected with separate tails to a henley block? Or is one rcd actually acting as the main switch?
Can we have a pic, we like pics!
are the two rcds are connected with separate tails to a henley block? Or is one rcd actually acting as the main switch?
Can we have a pic, we like pics!
Yes, but it still must have a single Main Isolator Switch.
Sponsored Links
We've been using the 17th edition boards at work for a few years now, the 100A Main switch disconnects the whole board, then you have two RCD's which control the seperate sides of the split load!
In this case there was no seperate Main Switch outside of the CCU, I assume one of the RCD's was acting as the Main Switch, as it seems that they had just replaced the MS with the RCD in a standard MK split load board.
As for the supply type, if I remember correctly from my college days it's TT (overhead power lines, earth rod used), so everything has to be covered by an RCD but also I think a main switch should be used.
In this case there was no seperate Main Switch outside of the CCU, I assume one of the RCD's was acting as the Main Switch, as it seems that they had just replaced the MS with the RCD in a standard MK split load board.
As for the supply type, if I remember correctly from my college days it's TT (overhead power lines, earth rod used), so everything has to be covered by an RCD but also I think a main switch should be used.
In that case, an S type used as main switch is OK
You'd need to look at where the meter tails go but (as JD says) for a TT the incomer must be a Time Delayed RCD (S Type). Its usual for this to be a 100mA trip RCD. The second RCD, protectcting items such as sockets, would be a standard 30mA RCD.
See the nice picture in the On Site Guide...
See the nice picture in the On Site Guide...
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
