Mains extension leads - daisy-chaining

Carrying children in cars was much simpler in the past. You just poured them in until it was full. Children sat on adults' laps where they could be controlled. The only restriction was not on the driver's lap. The driver breast feeding an infant was frowned on too.

AKA Bryant & May connectors

I had the same with the kettle of a postgrad physicist, save that her plug had been fitted by a another postgrad physicist - one of the cleverest people I've ever met. Made me feel ashamed of the brand.

Having just become grandparents, we've been immersed into the world of ISOFIX products and compliance !

A quality 4 way block using the correct flex will not have a problem with a 3kW load. Indeed a quality 4 way block may well have a 13 amp fuse fitted - in addition to the one in the plug.

As a small child, my favourite seating place in the car was sat astride the front armrest in the bench seat in the front of Mum's Morris Oxford. It gave a commanding view of the road and I could see all that was going on.

(After the day I kicked it out of gear while travelling in the outside lane of the A127, causing an unexpected loss of power, it was decided that I was getting too big for that lark and I was relegated to a proper seat! :-)

Even at that age you were taking an interest in such things?

Bill

When I was five my dad got rid of the motorbike and sidecar and bought a tiny Bradford van. I hated it because it was too big in the back and I cannoned about when he went round corners or braked. Eventually he got a bus seat for me.

Bill

The first thing I ever smiled at was a light bulb (It might be the last too).

One of my favourites was when one of the less practical graduate design engineers was working in the electronics lab. On enquiring if there were any spare 13 A plugs for his soldering iron, he was pointed towards the SafeBloc (1). Some time later it was noticed that the SafeBloc was still on the bench, but it no longer had its plug!

(1)

Chris

Eventually this progresses to "Grandad, I really need a car. I don't suppose..."

Bill

Doesn't he die, theatrically?

Bill

Oh yes, he does!

Bill

You'd have thought the leccy would have made his beatlecut stand on end

Bill

No, but they are requited to meet BS requirements. Though there's a loophole which avoids the requirement for a minimum distance between the earth pin and the edge of the body which enables a plug to be inserted

It's not the "average" power that matters.

It's the peak power and starting torque of motors.

Anything that compresses (like air conditioners), the starting transient is significant. You'll see the lights dim for a brief moment.

Some mechanical loads are gentle. A fan blade, only the initial inertia needs to be overcome. The mechanical load rises as the fan accelerates up to speed.

A compressor is a different matter.

Paul

Good theory, but the start-up took about a minute before useable oxygen was produced and any problems would only become apparent after that.

Where startup load is a problem, compressors can be started with either an open bypass valve(s) or using unloaders (which force the inlet valve(s) to remain open), so any gas is simply pushed out and back to the inlet, without being compressed.

It's not so much the plugs and sockets as the cable resistance.

For a 1.25mm² cable, max length of an extension lead fused at 13A is

Extension leads, like Asprin, are something that would never be allowed nowadays if it wasn't for the fact that we've been using them for decades with insufficient protection without all being killed.

Andrew Gabriel