40A Isolator MetalClad or ABS

[Spike1947]

Hi
I am wanting to purchase a Metal Clad or ABS 40A RCD/MCB isolator to feed a 40 Tube Sun bed, not quite sure whether to get just the 40A RCB or get a 63A RCB with a 40A MCB , something on the lines as per pics shown, I need it to be as small a foot print has possible.

cheers

Spike

 

[buzzlightyear]

am wanting to purchase a Metal Clad or ABS 40A RCD/MCB isolator to feed a 40 Tube Sun bed, not quite sure whether to get just the 40A RCB or get a 63A RCB with a 40A MCB , something on the lines as per pics shown, I need it to be as small a foot print has possible.

Have you worked the loading out before you asking this question.

 

[Spike1947]

Have you worked the loading out before you asking this question.

Yes

 

[loz2754]

Obviously an RCD doesn't provide overcurrent protection, so if this enclosure is to be fed by an overcurrent protective device, then just an RCD is all you need.
Otherwise, your enclosure will need to have either an RCBO, or an RCD and MCB of the correct type and rating.

 

[Spike1947]

Obviously an RCD doesn't provide overcurrent protection, so if this enclosure is to be fed by an overcurrent protective device, then just an RCD is all you need.
Otherwise, your enclosure will need to have either an RCBO, or an RCD and MCB of the correct type and rating.

So something like my first picture posted !

 

[loz2754]

So something like my first picture posted !

Yes

 

[westward10]

Obviously an RCD doesn't provide overcurrent protection, so if this enclosure is to be fed by an overcurrent protective device, then just an RCD is all you need.
Otherwise, your enclosure will need to have either an RCBO, or an RCD and MCB of the correct type and rating.

It's a bit blurry but the Contactum one would appear to say B40.

40 Amp 30mA RCBO - Contactum - Type AC - B Curve - 2 Module | Contactum (CPBR402)

 

[Spike1947]

Need a 40A supply from the CU to feed the Bed, was just going to put a 40amp double pole RCBO just above the CU, then feed the 6mm2 cable direct into the Bed ! .

Spike

 

[loz2754]

It's a bit blurry but the Contactum one would appear to say B40.

40 Amp 30mA RCBO - Contactum - Type AC - B Curve - 2 Module | Contactum (CPBR402)

Good eyes!

 

[Spike1947]

Will this do !.

Spike

 

[westward10]

Use the Contactum one not that Europa rubbish.

 

[Spike1947]

Yes will do, just trying to work out how to take the feed from the CU , not sure if I will get 2 sets of tails into the 80A RCD in the CU ! .

Spike

 

[westward10]

Lashing tails into the existing rcd isn't really the way forward.

 

[Spike1947]

Lashing tails into the existing rcd isn't really the way forward.

Yeh , have a spare Henley Block ! .

 

[telectrix]

if you're feeding from a RCD why add another RCD?

 

[westward10]

Yeh , have a spare Henley Block ! .

Not really sure what that means but if there are no spare ways I would fit a suitable isolator through to service terminal blocks through to the existing board and your new supply.

 

[buzzlightyear]

Yes will do, just trying to work out how to take the feed from the CU , not sure if I will get 2 sets of tails into the 80A RCD in the CU ! .

Maybe you should get some one to sort the job out for you.

 

[MJPD29]

What is length/ method when using 6mm on 40a mcb?

 

[Spike1947]

Can anyone tell me if this is a correct statement, quote: Power requirements
Most people underestimate this, even some electricians if they haven’t installed a sunbed previously. As a
rough guide, a 200 Watt lamp uses about 1 Amp of electrical current, so a 40 tube 200 watt sunbed uses
around 40 Amps, which equates to 9.6 Kilowatts.

This means that the cable supplying power from your
fuseboard to your sunbed room needs to be 10mm (size in cross sectional area) which is thicker than most
shower or cooker cables. A 60 tube sunshower needs 16mm cable.

Its amazing how many people think that the sunbed can be simply plugged in to a conventional socket ! A 13 Amp plug has a maximum power capability of 3 Kilowatts before the fuse will blow.

What’s more, a sunbed is what’s called an inductive load. This means that when it starts up, it draws around
10 – 20% more current during the first few seconds, just like an electric motor.

Many electricians do not realise this, and although it does not affect the cable size required, it does affect the size of the circuit breaker (fuse) in your fusebox. If the 40 tube (40 Amp) sunbed in the example above was supplied via a 45 Amp circuit
breaker, it would trip out on start up, giving the impression that the sunbed was faulty.

There are two solutions: one is the obvious, to fit the next size up circuit breaker. Unfortunately, this is either
50 Amps, or 63 Amps. The wiring regulation do not recommend a 63 Amp breaker to protect a 10mm cable,
as it results in a mismatch that can be potentially a fire hazard, so a 16mm cable would be required, which is
much more expensive, and cumbersome to route through your shop due to its larger physical size.

The other option is to use a Type “C” circuit breaker in the fuseboard. Electricians call these ‘motor start
breakers’ and these allow a higher initial start-up current to flow without tripping, as used on industrial electric motors.
Problem solved! . :unquote.

Spike

 

[James]

have had a quick look, wow they do come in large power requirements.
at that power, a normal electrical supply in the uk could only power 2 of them with some spare capacity for heating and lighting etc.

I note they are available in 3 phase versions, this would dramatically reduce your cable sizes and perhaps be easier to install.