Brain teasers

dingding

SteveC wrote: »

Good idea - I'm enjoying these...:D

+ 1

watty

SteveC wrote: »

crossover switches?
standard domestic but rare IMO.

yes.

you can have as many as you like inserted on the two wires between the normal 2 way switches.

PWR --<====x=====x====x====>----0----Neutral

5 switches. Any switch will turn light --0-- on or off

hall to kitchen and upstairs.

Have a switch at kitchen door end of hall, one at front door(X over) and one upstairs. Very under used.

But then we have builders that think one double socket per room is enough. The problem isn't the poor Sparky but mean developers. Then people end up with extension leads and 4 way or 6 way socket strips everywhere and a gazillion adaptors. It's one thing to wire extra sockets when you are building a house but VERY expensive to add them flush with no visible trunking afterward.

A VIRTUAL Beverage of your choice to all who spotted how simple it is.

DublinDilbert

watty wrote: »

But then we have builders that think one double socket per room is enough.

This indeed is a major problem... in fact a house can be certified even if there's only one socket in it, once that socket is required correctly...

In places like the US/Canada the building regulations will require you to have a double socket every x number of feet on each wall!! this is to prevent people using extensions / plug boards....

Karlos_Sparky

Sorry about the delay in getting back - it was perfect ...... and the 1 way switch had to be kept but it was just in the circuit as a master off ........

I will ask for a few more of these brainteasers ....

watty

DublinDilbert wrote: »

Ahh that's too easy...

But is it safe or Legal?

What if it's an ES fitting? Very common on PAR/Spot bulbs. Though I have a set of 3 spots with BC fitting and very few places stock the bulbs, most only have ES version.

dingding

Sorry for confusing, It was meant as an electrical circuit brain teaser not as meeting electrical regulations, I should perhaps have modified the question to say it the solution does not comply with electrial recs.

More puzzles please

watty

I learnt my wiring skills in UK, so I'm not always sure, e.g. in UK you must not (In my time) bond neutral to earth and here the neutral must be bonded to earth rod. That's a pretty major difference!

The fuse boxes used to be generally different. The circular screw in fuse not in UK.

dingding

watty wrote: »

I learnt my wiring skills in UK, so I'm not always sure, e.g. in UK you must not (In my time) bond neutral to earth and here the neutral must be bonded to earth rod. That's a pretty major difference!

The fuse boxes used to be generally different. The circular screw in fuse not in UK.

I think the older UK fuseboards had rewireable fuses. The Irish system if installed correctly with gague rings is probably safer.

Stoner

Remember you can always just post that you know the answer and give others time to work it out.

Steve

Good call Stoner. This could be a bit of craic..:D

Mr Magnolia

Right.

3 gang light switch in the hall. One of the switches controls a light in a room not visible from the hall. The other switches are unused. How do you figure out which switch controls the light?

Rules:

You can do what you want with the switch positions before you leave the hall.
You have only one opportunity to go from the hall to the room.
You have no way of seeing if the bulb is on or off before going into the room
You can't open the light switch.



x1.
x2.
x3.

______________________________________/ Door _______

-o (light bulb)








I may be omitting other rules, this will become evident...

Stoner

Ok Mr. Mag i think I have this one, we need some other element to use as part of the process and i think i have it now, I'll pm you the answer

Michael Collins

Ok I can't wait any longer, I have to show off!

I'd do it like so:

Turn Switch 1 On
Turn Switch 2 On for a few mniutes and then off again
Leave Switch 3 untouched

Now go into the other room and check:

If the light is on, it's Switch 1 that controls it.
If it's off and warm, it's switch 2.
If it's off and cold, it's switch 3.

This assumes that a) you know when a switch is on or off and b) the bulb is working and procduces a reasonable amount of heat! Not sure if it'd work with some LED lights...

It's just a small variation on the problem that we had earlier with the three lights.

Stoner

yep, the other element to add was heat, that's a great one lads, well worked out Michael Collins

brightspark

Here's an alternative answer to dingding's earlier post


http://www.mkelectric.co.uk/news/news.asp?newsid=1055

he did allow "any switches you like to purchase":D

brightspark

Here's a teaser for you

You just called round to a friend's house and he tells you he thinks the fuse in a plug top is blown, but you only have a simple phase tester in your pocket.

You know the socket is ok as you were able to test it with another appliance.

How can you check if the fuse has blown?

Steve

I actually had to think about that one brightspark.. good question.

Would you would stick the fuse on the user end of the phase tester and your finger on the end of the fuse?

Stoner

use the phase tester to open the plug on the other appliance and change the fuses over, if the previously tested appliance works then the fuse is fine, if not then it wont.

Might not be the most inventive option, but it's what I would do