Here’s a sure red flag the home contractor you’re considering is untrustworthy | 25 Amp Circuit Breaker

Yeah really though. It’s kind of embarrassing. I’m an engineer and work in big industry (usually minerals, bulk material handling, oil and gas, doing a big robotics project right now for a wood products plant, etc.) and this would be an afterthought. No one would even question it. I mean really a no brainer. People use electric blankets on their bed. I really don’t get it. It really shows how amateur hour most of the people who comment on this site are.

Many will ask what protects the circuit in an overload condition between the MCA and MOCP ratings? In these overload conditions, the overload protections on the motors themselves are designed to protect the circuit. If the overload protection on the compressor or fan motor fails, the windings in the motors have a far lower ampacity than the branch circuit and will fail open or shorted before the branch conductor will fail. In the case of any significant ground-fault short, the overcurrent protector (breaker or fuse) will still protect the circuit.

It’s the peak rating. For constant loads, or anything that could be temporarily constant you need to de-rate.

So it’s the usual forgettable Toyota – but still hugely preferable to the godawful Prius which is a truly horrendous looking vehicle 

The standard in UK is 230 V not 240 V, like the the rest of the EU. The continent was mainly using 220 V until 1986 and UK 240 V until 1986. The 230 VAC was choosen by the IEC as a compromise between the 220, 230 and 240 system. So actually main voltage in EU should be 230V +/-6% at distribution panel, and equipement should support 230V +/-10%. (voltage drop in the internal house distribution should be less than 4%) But a transition period of 20~25 years was used, during the transition period main voltage at distribution panel in UK should be in the 230 VAC +10%/-6% range, and in the rest of EU it should be in the 230 VAC +6%/-10% range. (Other 240 VAC country like Australia and NZ switch to 230 VAC at least officialy)

And in my own experience, I have seen switch mode power supplies designed for 400 volts DC (280 volt AC), taking clearance for such into consideration throughout the whole design.

Funny story : one of my friend had a real electrical problem in his house : earth not well connected or whatever. You could get shocked by touching an USB shield while bare foot. Handling something without a case like a raspi was a living hell.

Most systems now do not distribute ground (earth) from the MV / LV substation. At the sub the neutral is connected to ground through a low value resistor (<1 ohm) to a nest of earth spikes. Live and neutral are then distributed. At the house Neutral will be connected to a suitable ground point and at that point the earth connection is split off from the neutral. This means that any difference in ground potential is slowly leaked through the big resistor at the substation and it is a big resistor, looks like an oil tank maybe 2 metres high and 1.5 metres across. It is also normal that if there is any equipment at a pole it will also have an earth nest for the neutral wire.

Please check Power Integrations LinkSwitch-TN devices:http://ac-dc.power.com/products/linkswitch-family/linkswitch-tn/

“I don’t think” – hehehe I’ll agree with that. My utility company provides 3rd world electricity in August. Most days the juice drops to 103 without anything on in the house. I’d love to have as much as 110. Fortunately, the L1 car charger works down to 100, and the L2 stuff works at 187 – the lowest I’ve measured. 5 big reasons why the juice is so bad, but then I’m not paying for the loss, so its not a biggie with me. Just worry a bit about the refrig and freezer.

My friend died of electrocution while on the job. Our mains voltage here is 240V (single phase) or 415V (three phase) and not very forgiving.

There are split-phase premises supplies and three-phase. Split-phase is used for residences and small businesses, and three phase is used for larger businesses and some larger multi-tenant buildings. When using two of three phases, they’re 120 degrees apart and the nominal voltage is 208 volts. When using both sides of split-phase, the two are 180 degrees apart and the nominal voltage is 240 volts. The nominal voltage from one phase to neutral is 120 volts.