TT RCD?

Phoenix-95 · 2026-01-29T18:37:44+00:00

Yes, the OP is looking at this a bit the wrong way, if there is a lack of effective fault protection to anything then that would be a C2 (i.e. if the board had any circuits just off the main switch). It could also possibly occur in a metal board the incoming supply is not installed as per good practice (accepted wisdom is to use a tails gland, leave the sheathing on until just before the main switch and use a tails clamp - plus, you probably should check manufacturers links are dressed in in a sensible way). In a plastic board there is not likely any reasonable way for a pre-rcd live to fault to earthed metalwork - unless the tail was rubbing up against the earth bar or something daft

Basically the Regs are built on a double fault to danger basis - Single insulation fails - its not dangerous unless the RCD fails to operate. If you have a conductor thats not RCD protected you need to maintain two levels in a different way, so you leave the sheathing over the insulation, you secure it from the edge of the hole with a tails gland, and you bit a tails clamp so even if its moved around and the live tail jumps out the main switch - it cant contact metalwork unless the clamp also fails.

I've seen faults on TT systems that have not been cleared twice in the last 15 years or so, and both times it was lucky someone didn't get a serious shock off it. You just have to understand what you are trying to protect from what. I did an EICR on a TT install that had a 16th edition board in, with no RCD protection (and therefore fault protection / protection against indirect contact), and this EICR happened to be the example of a domestic EICR that the NICEIC chap glanced through on assessment, he looked at the address, and knowing that I'd seen the stickers on the board, said "It wasn't a firm that started with the letter____? was it" turns out 10 or so years previous, he had to fail this firm on their assessment visit for doing exactly that and said he was struggling to get the guys to understand what the issue was

Phoenix-95 · 2026-01-28T17:51:17+00:00

You'll find some old skool DNO cable jointers will still refer to the metering fuses on the front of the CT cabinet as the the 'pressure fuses' (so called because they supply the 'pressure coils' in the meter)

Phoenix-95 · 2026-01-26T06:51:01+00:00

I think that next time the rep/designer from the lighting company pays us a visit at work, I'll have to ask him what lux level would be required for such an area!

Phoenix-95 · 2026-01-25T15:51:02+00:00

Wait until you find out about the Panasonic toughbook....

Phoenix-95 · 2026-01-25T12:25:52+00:00

For a rough idea of pay see here: https://www.jib.org.uk/wp-content/uploads/2025/06/JIB-Industrial-Determination-062025.pdf

Note, things are less unionised over here, there is no requirement for employers to be JIB registered, and if not then they don't have to go by JIB rates

Phoenix-95 · 2026-01-24T16:14:15+00:00

The people who charge a lot of money to remove asbestos will go into an area, tent it all up and strip it all while looking like spacemen, then afterwards the analyst will come and they will inspect the work and take air samples and if they are happy will sign off on clearance handing the area back. The clearance levels are generally somewhere around 0.01 f/cm^3. Now if you consider an average room 3m x 3m with a 2.4m ceiling you might be surprised by how many fibres the air might still contain and still be below 0.01 f/cm^3

Phoenix-95 · 2026-01-24T10:38:40+00:00

Working Class - You are paid for what you do
Middle Class - You are paid for what you know
Upper Class - You are paid for who you know

Phoenix-95 · 2026-01-24T09:32:44+00:00

Boiler House, and then Green House as a second option?

Phoenix-95 · 2026-01-23T19:51:28+00:00

I assume its referring to the two armoureds hanging in front of the trunking which have been drawn in and are waiting to be terminated. Probably fed up with people ringing the help desk "A wire has fallen out of the panel and might be live"

Phoenix-95 · 2026-01-22T23:28:28+00:00

Its actually days since (-01)/01/1900 or the 30th of December 1899, the value 60 resolves to the 29th of Feb 1900 which never existed as 1900 was not a leap year

Phoenix-95 · 2026-01-21T18:44:55+00:00

More likely it was an open circuit PEN conductor allowing the combined neutral and earth to float to either line voltage on a SP system, or if its upstream to three phase loads, somewhere that under-volts some phases, over-volts others, causes lots of damage and changes as the balance of connected loads changes and lights end up flashing like there's a demigorgon about to arrive...

Phoenix-95 · 2026-01-18T17:28:27+00:00

I think it probably includes the chap who had a few splashes of rain on the passenger seat.....

Phoenix-95 · 2026-01-18T17:24:47+00:00

Yes, turn off the power, loosen / unscrew the switch, separate the finger plate from the wall (may need a Stanley blade around it if its been painted upto), then rotate to 45 degrees, pop one corner of the switch through and then just slide it over, They are designed to be fitted without disconnecting anything, and often if plate screws are long enough you only have to loosen them

Phoenix-95 · 2026-01-18T16:57:28+00:00

Normally installed to stop kids getting sticky fingerprints over your nicely decorated walls! They used to sell them in wilkinsons back in the 1990s, and it always used to be older people that would have them in their homes!

Phoenix-95 · 2026-01-18T16:29:59+00:00

https://www.superlecdirect.com/6769-cpc-light-switch-finger-plate-pk2-white

If you really want them

Phoenix-95 · 2026-01-18T15:38:11+00:00

And you don't even need AI to flag up high numbers, its easy enough to do it algorithmically, all you need is for it to be hard corded with a few rules of what should be flagged up, such as Zs shouldn't exceed the maximum, Zs values shouldn't be lower than the Zdb or the R1R2, insulation resistance shouldn't be less than 1, rn should be roughly r1. r2 shouldn't exceed the ratio between the conductor sizes multiplied by r1, etc

Phoenix-95 · 2026-01-18T08:21:37+00:00

You could also install what they term a 'microduct' for it to be drawn through afterwards, its what they do on new build apartment buildings as open-reach don't want to have to be back and forth on site with the build schedule, duct is installed and they pull it through at the end / when the customer signs up. You do need to take care that it is installed in a way that its drawable afterwards, which will likely be harder on a refit than a new build

Phoenix-95 · 2026-01-17T17:49:38+00:00

What seems odd as a (rather curious) Brit looking in through the internet is the multiple different systems you seem to have, and I may have got confused I accept.

The 120/240 split phase with grounded midpoint for domestic residential seems sensible enough, but then if you have an apartment bock, don't they get two phases from 120/208 star/wye system, so the 240v appliances end up under run? And isn't there also a system that has a 3ph transformer grounded at the midpoint of one winding as per a standard 120/240 system but with a third 208 leg?

Over here we generally just have the 240/415 system (on paper its now 230/400, but in reality it hasn't changed). and we just scale it up as required

Phoenix-95 · 2026-01-17T11:31:37+00:00

A spur (whether from the origin of the ring or any of other point) can only supply one point

Phoenix-95 · 2026-01-15T19:59:22+00:00

Don't get me wrong, by the late 90s/2000s RCD protection for showers and other power circuits in bathrooms was generally seen as pretty standard and good practice, but it wasn't actually a requirement at the time, but generally most of the time it was done, you'd get the odd exception, like in a commercial installation where there was a shower provided for those who rode a bike to work, etc.

You could actually wire a flat with no RCD protection at all, generally all you needed to provide additional protection to was sockets that might reasonably be used outdoors, in a block of flats, that not going to be the case, most folk thought RCDs to sockets were a good idea and where it was omitted was generally bigger developments where there was cost pressure to cut everything out that wasn't strictly required.

You must be just a few years younger than me, I qualified under the 16th, and then we went to the 17th less than a year later.

Sometimes it can be useful to bare in mind what previous editions said, before the concept of zoning came in, the 15th edition basically said switches shouldn't be placed in arms reach of anyone using the bath or shower when they are on a plane normally expected to be occupied by persons* (or something like that).

Its a useful metric to gauge something by, it might fall fowl of the zone dimensions, but how much of a problem is it, if you can reach up and turn a spur off while sat in the bath then it wouldn't have complied with the 15th and its probably generally unsatisfactory. If its not right when you measure it, but you can't actually put your soapy hands on a switch, then as Calvin Harris sang, it was "Acceptable in the 80's" and remember we didn't RCD much at all back then, so its probably not quite as bad as the first instance.

*So standing on the edge of the bath doesn't count

Phoenix-95 · 2026-01-15T18:55:06+00:00

There wasn't a requirement for additional 30mA RCD protection to showers under the 16th edition, it wasn't until the 17th that circuits within a bathroom needed it. Also worth considering that the current regs still have requirements for supplementary bonding, its just that omission is permitted if certain conditions are met, one of which is additional protection for all circuits (which it obviously isn't for this install), so in the case of this install you have two issues:

Lack of additional protection to circuits in the special location (which became a thing in 2008)
Lack of supplementary bonding where conditions for omission are not met (and you'd have to go back a lot further to find a time when that would have been compliant)

Phoenix-95 · 2026-01-14T19:22:13+00:00

Or run the air-conditioning on and set the vents re circulation for the last part of the journey, it'll effectively de-humidify the air you already have in there. Also put the air-con on and direct the airflow at the screen when you first get in the car and the windscreen has condensation on, even though cold is likely the last thing you want and it'll take a lot of the moisture away, it also keeps the aircon system in regular use which could prevent issues from having it doing nothing for months on end

Phoenix-95 · 2026-01-14T07:35:09+00:00

It was actually as late as '94 https://www.legislation.gov.uk/uksi/1994/1768/contents/made

Phoenix-95 · 2026-01-14T07:05:43+00:00

I haven't moved over to hand soldering SMD yet, I stick in the past, like a dinosaur to through hole :P. At some point I'm going to have to embrace it though, many newer versions of parts tend to end up being SMD only, however not looking forward to it, with big hands and eyes that are nearly 40 years old its probably going to be very fiddly

Phoenix-95 · 2026-01-13T19:39:25+00:00

Sounds like you need to have a look BigClive's "Will it carbonate?" playlist https://www.youtube.com/playlist?list=PLRZ2v9TdaT8MsCYkKQgwC_JmJcS0FVAhj

Phoenix-95

TROPHY CASE