10.8kw showers and cables!

[Dunce]

To be honest I hadn't considered it.

The last shower, fitted over 12 years ago, didn't have one.

I don't really know much about RCDs. Can you get combined RCD/MCBs?

I'll certainly put in now.

 

[sparkwright]

Yes.
These are known as RCBOs.

What is the make and age of your consumer unit?

If it is a split load board you will have an RCD (RCCB) protecting some of the circuits.

 

[Dunce]

Untitled

• Dunce
• 6 Feb 2011
• 1

Untitled

• Dunce
• 6 Feb 2011
• 1

It looks like it's made by Proteus. A fairly old thing - about 15 years.

 

[RF Lighting]

Unfortunately those circuit breakers are now obsolete, and there was never an RCBO made for that CU.

You could how ever fit an RCD for the shower in a seperate enclosure next to your CU.

You really really sohuld RCD protect this circuit.

 

[Dunce]

Unfortunately those circuit breakers are now obsolete...

Oh hell. So I'm not actually going to be able to get a new one?

I'm jjst looking now and not having much luck!

 

[sparkwright]

Unfortunately those circuit breakers are now obsolete...

Oh hell. So I'm not actually going to be able to get a new one?

I'm jjst looking now and not having much luck!

No, you won't get an RCBO or an MCB.

Don't know of any current makes that will fit.

You could change the whole consumer unit that meets 17th edition, ie RCDs on all appropriate circuits.

Or you could fit a separate fuse board alongside. The usual way to do this is use an RCCB (rated at 63 amp or above) as the main switch, with a 45 amp MCB. Or a 63 amp main switch, with a 45 amp RCBO.

Normally an Isco block can be fitted between your meter tails, and new tails go to this enclosure.

Either way, not really a DIY job, but all in a day's work for an experienced electrician.

 

[OilLecky]

I think that most of your questions have been answered Dunce and it is all good information. Especially pay attention to "The usual way to do this is use an RCCB (rated at 63 amp or above) as the main switch, with a 45 amp MCB. Or a 63 amp main switch, with a 45 amp RCBO" and "tight connections".

The bit that hasn't been answered is about a 40 Amp Circuit Breaker which may occaisionaly pass 47 Amps. When the current passing through a circuit breaker, or fuse for that matter, exceeds the rating, it does not trip straight away. i.e. a 40 amp circuit breaker would not trip if 41 amps was passing through it. In fact the circuit breaker will take quite a large overload before it trips. The time taken for it to trip depends on how much higher the current is than the rating. So occaisional surges to 47amps should not cause a problem but if you had the shower on for an hour at 47 amps it will trip.
As an example a 40Amp,Type B Circuit breaker, needs 200Amps to pass through it, to trip between 0.1 and 5 secs. It should take 47Amps for about 30 secs before tripping.

 

[ban-all-sheds]

The nominal 230v figure applies to new supplies only, some europeans decided it was a nice number. Old supplies will remain at a nominal 240v forever,

Please go and look up what the word "nominal" means.

the main reason being if the voltage was reduced the electricty bill would also be reduced.

There's a job for you selling those voltage reduction devices which are supposed to save people money - you could walk straight in as you wouldn't need the obfuscating charlatan training first.

 

[ban-all-sheds]

If the cable installation is actually in conduit and insulation through its length, which I doubt, then I would down-size the circuit breaker to 40amps.

In ≥ Ib

 

[holmslaw]

..

 

[ban-all-sheds]

Something that exists in name only.

i.e. like a declared supply voltage of 230 +10% -6% or 240 ± 6%

The only only device I know of is the 'powerperfector' and it will save money. Have a look http://www.powerperfector.com/[/QUOTE]
For the major uses of electricity in the home please explain how changing the voltage supplied to appliances will save money.

Why are you being nastier than usual?

A bit like you a nominal human being.

 

[holmslaw]

..

 

[holmslaw]

..

 

[ricicle]

Ah, you must be one of those people who think that kilowatts do not vary with the applied voltage. Less voltage = less kw used = less kwh = less money to pay. or is that too complicated for you?

Oh dear - back to physics school then is it Holmie ?

I need to boil my kettle - will reducing my incoming voltage mean I use less energy to boil it ?

 

[ban-all-sheds]

Ah, you must be one of those people who think that kilowatts do not vary with the applied voltage. Less voltage = less kw used = less kwh = less money to pay. or is that too complicated for you?

For the major uses of electricity in the home please explain how changing the voltage supplied to appliances will save money.

For example, if the voltage to a kettle is reduced, please explain how fewer kWh will be needed to boil the water.

Unless, of course, that's too complicated for you.


Edit - I see that ricicle has already asked you about the kettle, so when you've answered that perhaps you could apply the same theory to explain how it will cost less to have a washing machine or dishwasher heat a given volume of water to a given temperature?

Or how an electric hob would use less energy to cook a given amount of food?

Or how an electric oven would use less energy to reach and maintain a given temperature for a given time?

Or how a tumble drier would use less energy to evaporate a given amount of water from clothes?

Or how a fridge/freezer would use less energy to maintain a given temperature, or freeze a given amount of food?

Or how anything with a SMPSU would use less energy to maintain a constant output voltage?