Afternoon All,
I have been silently "lurking" on this forum for quite some time and found the advise to be given really helpful and I myself have learned quite a bit as well.
Always good to see a lurker spring to life 
Now it's my turn - I have a query for the learned members on this forum regarding my own house main DB.
The DB in the house that I bought 9 years ago has always been an eyesore but I've managed to successfully pretend it didn't exist until recently. How it managed to get a CoC when I bought it is a mystery but considering the previous owner was the estate agent and her husband the conveyancing attorney, I suspect some special arrangements were made.
After a recent heavy and damaging downpour in my town, the main incoming municipal cable was damaged. A colleague of mine, the local sparky, who did the repair mentioned that I really need to sort my DB out - he's told me this on a few occasions.
Now the questions:
1. I have too many breakers for the existing panel, it has been modified as the house was extended to squeeze a few extra's in.
If your circuit breakers are older generation it may be possible to replace the breakers with new ones which are smaller in width, this alone may free up sufficient space for the extra circuits. Maybe post a couple of photos of the DB if you can.
I am considering placing a surface mount box on top of the existing flush mounted box - probably a larger dimensioned box to fit two rows of breakers. Is this allowed?
Yes, it can be done but it's not in the realms of DIY work so maybe have a discussion about it with your sparky. Is it not possible to remove the old DB and neatly cut in a larger new flush mount enclosure? Surface mount DB's tend to be obtrusive.
2. Leading on from the above, some of the circuits (lights, plugs) have two wires out of the single pole breaker - is this allowed?
Difficult to say without more details but generally this would be bad design at best and downright non-compliant at worst and most times I've come across this it's the latter.
(Another reason to fit a bigger box. Also to incorporate additional ELCB's to eliminate nuisance tripping, which I have occasionally)
One word....testing!! Again, another reason you need to discuss the design with a sparky. The majority of nuisance tripping faults are because of faults on circuits and/or appliances. Without testing and remedying of faults there's a high liklihood that adding earth leakage circuit breakers won't cure the problem.
3. As I anticipate the wiring to be too short, is it legal to fit a terminal rail into the DB, which will allow the use of shorter, extension pieces from the CB's to this terminal rail? (Terminals such as Weidmuller SAK 2.5 or 4 or equivalent legal terminals - I'm an Instrument Tech by trade, hence my familiarity with using terminals in JB's.)
Extending of circuits can be done using DIN mount terminals in some circumstances but properly indent-crimped ferrules insulated with 2 layers of heatshrink would be a better result in my (old fashioned) opinion, especially if access to the connections is limited or unavailable in the future. Wago connectors or the Helacon or similar are also great although somewhat bulkier, just depends on space and personal preference. Some of the DIN mount terminal blocks aren't good for single solid conductors, they're primarily designed for panel wire which is fine stranded.
I hope the above makes sense?
Many thanks,
Shaun.
p.s. - I have no intention of doing the work myself. I just want to be able to make an educated decision when scoping the job.
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Originally Posted by desertburner
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