Butchering a consumer unit Part deux | Page 2 | on ElectriciansForums

Discuss Butchering a consumer unit Part deux in the UK Electrical Forum area at ElectriciansForums.net

littlespark

-
Staff member
Esteemed
Arms
Supporter
Patron
Joined
Aug 12, 2017
Messages
12,650
Solutions
1
Reaction score
17,963
Location
Scottish Borders
Heating system in a local church which is basically tubular heaters under a few pews.

A local company has already quoted thousands to rip all this out and start again. The committee are reluctant to spend massive amounts as the building only gets used for 2 hours once a fortnight.
It’s old, but it all works.
[ElectriciansForums.net] Butchering a consumer unit Part deux


Main switch on left is always on to power everything here.
The silver box next is a contactor.... will get to that in a minute..
Next is the mainswitch for the fuseboard... they turn this on during the week before a service.... but only sends power to the top of the contactor.
Next is the fuseboard.... 6 fuses across 3 phases going out on the old twin and earths that disappear into the wall below it then go to heaters.
The rightmost MEM switch doesn’t get used. Neither does the circular mechanical time clock below.... which is marked as suppliers clock.
The electronic programmer beside it appears to have replaced another mechanical clock which energises the contactor coil.... the switch below that overrides the programmer.... which is now surplus to requirements as the electronic programmer has its own override button.

So, just to make things a little safer without tearing it all out, could I take the guts out the fusebox and install a DIN rail with rcbo’s?
Leave the box and lid as it is, but fix a Perspex shield with a hole for the rcbo’s to stick through so they can be reset, but all the connections are safely behind the barrier.

[ElectriciansForums.net] Butchering a consumer unit Part deux

Whew... long post.
There’s a fairly modern 4 gang plastic CU elsewhere serving lighting and power, so I’m quoting to change this to rcbo as well.

ps, the other box a foot below the switch is a room thermostat, and if it’s also surplus, it’s coming out for LN.
 
Sounds a bit too much like manufacturing custom equipment to me.

Don't get me wrong, I'm sure technically it is a good solution.
I agree. It's fine to screw a DIN rail into an old rewireable fuse enclosure like the one in question and fit MCBs with semi exposed live terminals, as long as the lid is secured by screws that require a tool, and it is labeled appropriately, and I have done so on a few occasions, but RCBOs, with their test buttons, means this solution can't be used.
 
I agree. It's fine to screw a DIN rail into an old rewireable fuse enclosure like the one in question and fit MCBs with semi exposed live terminals, as long as the lid is secured by screws that require a tool, and it is labeled appropriately, and I have done so on a few occasions, but RCBOs, with their test buttons, means this solution can't be used.
But if I make a “lid” which is screwed back.... but has a hole where the front of the rcbo’s protrude to access the test button and toggle switch.

The actual existing lid is a hinged door, which just happens to be held closed by screws at the moment.
 
If the right-most switch is no longer used, and the mechanical timer below it also obsolete, could you not just replace the box with the 6 rewirable fuses with a suitable DIN rail box and some RCBOs?

Space would be an issue, but you can probably take those cables in the rear of a box and the top mated to the trunking.
 
RCBOs, with their test buttons, means this solution can't be used.
What makes the test button on an RCD/BO any different to the trip mechanism on an MCB or even the pulling of the original ceramic fuse???
 
What makes the test button on an RCD/BO any different to the trip mechanism on an MCB or even the pulling of the original ceramic fuse???
Because you can do those with the power isolated.... rcd test button needs power to operate


yeh what he said ^
 
I'll need some serious convincing that everybody isolates an entire board to 'reset' an MCB, especially when they're rated for functional isolation (as also are RCBO's).
 
What makes the test button on an RCD/BO any different to the trip mechanism on an MCB or even the pulling of the original ceramic fuse???

Because an MCB only needs to be operated if a fault has occurred. The test button on an RCD should be operated periodically without any fault being present.
 
I'll need some serious convincing that everybody isolates an entire board to 'reset' an MCB, especially when they're rated for functional isolation (as also are RCBO's).
Whatever the manufacturers claim, closing a MCB live, against a short circuit, is neither good for the MCB nor my nerves.
 
The most common tripping event, In the days of tungsten bulbs MCB would trip whenever a bulb blew, if a home owner knew that and replaced the bulb, the short circuit had been eliminated so resetting the MCB would not be against a short circuit, not reliable for all events, but.
 
I have no idea why you are intending to create an ad hoc dist board. I would give them two options, divert the supply into an rcd which isn't ideal or completely replace the board. The fact they are not keen on spending too much money would be of no concern to me.
 

Reply to Butchering a consumer unit Part deux in the UK Electrical Forum area at ElectriciansForums.net

Similar Threads

So it was a poor connection between the busbar and the RCD - hence my pressure on the RCD was making the connection.
Replies
9
Views
2K
  • Question
The garden supply will have a 7kw sauna at a later date which has the 16mm swa 3 core to it
Replies
4
Views
1K
  • Question
I recall where a fluorescent capacitor would cause a separate socket RCD to trip when turning off the light
Replies
9
Views
1K
  • Question
Thought this was sounding a bit familiar. A thread on the same subject from 2021,, There's a link to the manual, but no diagrams, in my post #2...
Replies
23
Views
6K
  • Question
Obviously not a building/DIY forum so will keep it short but yes - we've taken all the floors up. Several joists in the bathroom need doing as...
Replies
8
Views
1K

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock    No Thanks