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This is fair. Is there any reason not to use flex? I have an interest in this problem because I put 2.5mm T&E though a 20mm conduit for a similar reason to the OP. In one run there was one 90 degree bend and one 45 degree bend. It came through eventually but it was very difficult. So I'm...

Could you strip the sheath off the T&E where it enters the conduit and pull the cores through as singles? I'm not sure what you do with the earth though.

Could maybe strip the sheath carefully, leave the cores intact and add splices with a short length of new cable to the light Would need some kind of box to clip around the joint afterwards

It also helps reduce the amount of interference picked up or emitted! I think the factor to consider in this context is the distance from the cores to any hall sensor versus the twist length in the cable. If it is small then the cores-in-a-plane approximation works better. So you might not get...

No. You could define a plane that's tangential to the actual ribbon/helix-like surface at a given position on the cable. But it's just an approximation to illustrate why you can measure a magnetic field outside the cable. I think the limitations of that approximation are one reason why devices...

Sounds clever! Did it work, despite the cost?

You could measure the phase of the voltage by capacitance. Place conductors on either 'side' of the cable and measure the electrostatically-induced voltage between them. Measuring the amplitude of the voltage would be more difficult because of the cable size/placement/arrangement uncertainties...

A cable with parallel cores could be seen as an extremely elongated, single-turn solenoid. So from a position above or below the plane in which the cores lie you would detect a magnetic field. Problem is, unlike in a normal clamp meter, you can't capture the flux for accurate measurement by...

Can you not just strip the sheath back to where the cable enters the conduit and feed it through as singles? As long as the conduit is continuous into the box.

Here's a diagram of how to do it

A standard thermocouple type thermostat measures the temperature internally then applies the differential sensed by the thermocouple. So all you would need to do, in theory, is disable or spoof the internal measurement and the thermostat will just measure the differential. Could even place the...

Road user pricing might be the alternative. It may be needed anyway when cars become self-driving since all that demand currently suppressed by congestion delays will be released once people can play on their phones all the time and they don't care how long it takes.

Can't you just power the socket from a spur from your flat? Or get one of those battery vacuums that they have now. Fire alarm could be powered from lighting circuit.

+1

Once I looked into making an H2Sstat - one that would turn a fan on automatically to vent noxious odours. I concluded that the human nose was far more sensitive than commercial hydrogen sulphide sensors and it would probably never operate.

Nice Coughtrie lamp fitting. You can probably get a replacement gasket if that is the cause of the problem.

Remember to send a copy of the electrician's invoice to the letting agents with details of your attempts to contact them. Deduct the amount you paid from your next rent payment.

I spy Chinese import typeface! For more information: http://www.raeknowler.name/cjk-typefaces

Unfortunately they already exist (the bimetallic version). You can get electronic versions these days but I expect they mostly need a continuous power source. OP: try searching for time delay relays. RS seems to have over 1000 types!

The time delay would vary with the ambient temperature, yes. But as long as the switching point was above the maximum possible ambient temperature it would still work. The heater temperature would increase with ambient temperature so there will always be a differential. A more complex thermostat...