MJNewton

I've never been too keen on the screw-in fixings shown (although have used the metal ones which are at least a bit better than the plastic) and would tend to use Fischer UX plugs now for direct-to-plasterboard fixing on non-heavyweight items. They scrunch up behind/inside the plasterboard and provide quite a secure fixing without damage to the board.

Or a combination of the two...

What colour is the cheaper ducting? If it's green or purple then it could well made by Blauberg which I found much less flexible (and even prone to kinking if pushing the radius limit) than the red Airflow offering. Of course if you won't be having any tight bends (ideal for airflow anyway) then this may not matter. That said, whatever it is that makes it less flexible might have other consequences.

Whilst it could be random, it is also quite common for it to be pseudo-random based on a hash of the requesting client's MAC address. This gives greater stability to allocations and thus helps with logging, avoiding problems by badly behaved DHCP clients (e.g. waiting for the lease to expire before renewing or holding on to addresses after the lease has expired) etc.

Given the inaccessibility anything with screw terminals won't suffice as there'd nbe no means for inspection and re-tightening should they creep/loosen over time. One option is crimps, but I wouldn't recommend that without a decent tool and some experience, and so I'd recommend instead something with spring loaded terminals. Wago do a 'Wagobox' that is classed as maintenance free when used with their terminals and Ashley do some maintenance free junction boxes with builtin terminals. Debox also appear to do a maintenance free version of the one you linked to. Apologies for the lack of specific part numbers and/or links but I am posting from my mobile so trying to be brief! Can post further details later if required.

It's not so much the colour temperature that we've had issue with but more the colour rendering... Interesting about the 'big brands' aspect though and maybe we should pick a few random offerings and see how they fare. Afterall, I wouldn't necessarily have expected Ikea bulbs to be such good performers.

My wife and I seem to be quite picky when it comes to lighting - too picky perhaps given the issues we're having... Our house is 95% lit by incandescent bulbs ('standard' and some halogen) and most rooms have dimmers. I am midway through building an extension to create an open-plan 'family room' consisting of kitchen, dining and lounge areas within which there will be fair amount of lighting. Sources include ceiling downlights, pendants and floor lamps. This seems to be the perfect time to move over to LED lighting, at least for the family room, and so we have been experimenting with different bulbs with extremely disappointing results. The main issue seems to be with the colour rendition (many seemingly giving things a green tinge, particularly our ginger cat who looks positively ill under a lot of them!) and disappointing performance when dimmed. We've only tried 2700K bulbs, on the assumption that this would get us the closest to what we're used to. We thought Philips would be a good bet, and was attracted by their 'dim tone' range which aim to emulate the warming of tungsten bulbs when dimmer (dropping from 2700K to 2200K), but they've been a real disappointment - the light they gave looked terrible. We also tried another bulb from them with a >90 CRI which was okay, but still not particularly pleasing. The best we've found are the Ikea Ledare range - high CRI (>90), warming function when dimming, good light and relatively cheap. The only downside is they seem to be discontinuing them as various bulbs from the range have gone through a 'Last Chance' phase on their website before now completely disappearing. Can anyone help? Perhaps we are just so used to the colour and colour rendering of incandescent bulbs that we just need a bit of time to adjust to LED? A bit like swapping from HD to SD sources on the TV; looks terrible on first transition but you gradually get used to it and it ends up looking okay. Or could it be our obsession with dimmers and that dimmable LEDs are limiting/eliminating our choice of good bulbs?

Whilst I'm no expert on the common causes of fire it wouldn't surprise me if the biggest risk in a (our) family room might be from faulty electrical equipment (AV kit, chargers etc) and perhaps candles rather than situations that heat alarms are aimed towards (eg chip pan fires?).

I am getting to the end of an extension to create a 'family room' - an open-plan kitchen/diner/lounge and am wondering what best to do about smoke/heat alarms.... Given the risk of false alarms I understand that a heat alarm is most appropriate for a kitchen however do they still perform adequately in a large room (9m x 5m)? There will be a defined kitchen area and so I was going to locate it there - perhaps above / to the side of the hob+oven? Or should I be looking at something else? (Maybe some sort of best-of-both-worlds combined affair that I might not be aware of?) The rest of the house used interlinked Aico alarms and so they would be my starting point, and perhaps finishing point too if alarms from different manufacturers cannot be mixed.

Following up on some of the mentions about hole limitations in I-joists, Simpson make an 'I-Joist Hole Support' that enables you to put holes upto 250mm wide (and full height of the webbing) anywhere you like beyond 50mm from the bearing points if need be.

I had a cut on my forearm that I didn't think much of but as it developed a scar I started to feel almost like there was something inside it. Casually mentioning it to the doctor one day whilst there for something else he sent me to hospital for an x-ray where they discovered there was indeed something inside... Two weeks later I am lay on a bed with my arm stretched out to one side with a plastic surgeon cutting my arm open. Local aesthetic so I was awake, and petrified (really quite squirmish) so when his assistant tripped over the wheel of the trolley table my arm was on I didn't see the funny side (I can now). Anyway, he pulled the object out and identified it as a piece of porcelain tile! Cue sudden flashback to six months earlier when I was chipping tiles off the wall and noticed a small cut on my forearm and wondering what had happened!

...not wishing to muddy the waters just as we were reaching some clarity but even a time-delayed RCD couldn't necessarilly guarantee the expected outcome as with a 60mA earth fault a 30mA RCD has a maximum trip time of 150ms and yet a time-delayed 100mA RCD has a minimum trip time of 130ms. That still leaves a 20ms window within which the time-delayed 100mA could end up beating the non-delayed 30mA potentially leaving the latter untripped. ? In practice I would expect it to work as intended though as non-delayed trip times are usually significantly shorter than what the standards require.

It is absolutely possible, yes, even if both devices are operating within spec.

It is more nuanced than that. The performance characteristics for RCDs are laid down by BS61008 which includes maximum trip times that vary depending on comparison to the rated trip current (In). This is necessary given the increased risk arising from increased exposure time and not just increased current. The base times specified are: Hence, an earth fault of 100mA would require a 30mA RCD (detecting 3.33 x 30mA) to trip within 150ms and a 100mA RCD (detecting 1 x In) to trip within 300ms but there are no *minimum* trip times specified (this is only done for time-delay RCDs) and so it is not possible to determine which would/should trip first. Moreover, for earth faults >150mA a 30mA and 100mA RCD would both be required to trip within the same maximum time (that's not to say they would do so if daisy-chained in the same circuit of course because an early trip from one may limit the exposure time of the other to the current imbalance).

I've just re-read and spotted there was a 5mm gap, albeit filled with foam?

If the studs weren't in direct contact with the wall (ie even just a small air gap) might that help?

Generally just TT earth systems where the supplier doesn't provide an earth, which can also include outbuildings where the earth isn't exported from the main building. Absolutely agree; I was just pointing out that even daisy chaining a 30mA downstream of an 100mA is still not good as it doesn't provide the discrimination that is often assumed to be the case.

This is not the case. Trip time depends on exactly that - trip time - you cannot with any certainty determine whether the 30mA or 100mA RCD/RCBO will trip first, regardless of where they are located. The only exception to this is if the fault current is between 30mA and 100mA in which case the 100mA RCD/RCBO will of course not trip at all. The only way of being deterministic is with time-delay RCDs/RCBOs which in most situations will undermine the protection that are usually employed to provide.

I've always regarded their price list as a catalogue of sorts, if that might suffice?

Yes, I was thinking about similar. Did you have a particular plan in mind? I assumed that a non-contact current transformer wrapped around the live feed would be the best sensor but wasn't sure on the best/safest place to do this given that the cores are only separated at each end where there's not much room to fit anything else like this? That said, I was assuming it'd be done at the hob/oven end but maybe inside the consumer unit would actually be the easiest place to do it?

For ours the RH sensor works extremely well for showers, baths, some cooking (boiling) and drying clothes... However, it's obviously no good for cooking smells so for that we've got a boost button next to the hob. Similarly, we have boost buttona outside the bathrooms but tend to rarely use them. The boost buttons are actually wired as inputs to a smart relay which, in turn, triggers the boost function as eventually once I get more time (yeah right!) I'd like to experiment more with home automation, voice control etc for various things which may or may not include the ventilation system.

That should be straightforward to recreate. Most (all?) MVHR units have boost inputs and as a boost switch in the kitchen makes sense anyway a non-contact current sensing relay wired in parallel (example) should work well.

Can you elaborate on the 'cooker hood mode' bit? Presumably, given the choice of words, it doesn't come with a cooker hood but is some sort of changed behaviour when the cooker hood is running? If so, I would imagine most units could be manipulated to do similar without too much effort (and a £10 smart relay) - unless the feature is more advanced than I am imagining.

Yes, they're got their own carriers.

The 221s arrived without much fanfare, and it doesn't help that the 222s are still around yet I would've expected them to have replaced them. They're such an improvement; easier levers and they have squared edges so can be 'stacked' a lot easier to reduce space.