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.

 

[Spike1947]

And this statement:
Sunbed/Vertical Tanning Unit Electrical Specification Fuseboard: Lie down sunbed: Single phase: Three phase: 80 Amp MCB 3 x 35 Amp MCB Vertical Tanning Unit: Single phase: Three phase: 100 Amp MCB 3 x 35 Amp MCB Residual Current Device (RCD/RCB/RCBO) is optional, but if fitted must be 100mA trip, not 30mA. Cable Single phase: 18mm Twin and Earth (Lie down and vertical sunbeds) Cable 3 Phase: 3 x 4mm (Lie down sunbeds) 3 x 6mm (Vertical sunbeds)

 

[Spike1947]

The part were it says use a 100mA trip as apposed to a 30mA !!

 

[pc1966]

The part were it says use a 100mA trip as apposed to a 30mA !!

Not uncommon for high power things. It is not to protect you here, it is usually for fire provention or in cases where it is a TT supply (earth rod, not a low resistance cable back to the supply).

 

[Spike1947]

Well people will be inside the vertical Sunbed !

 

[pc1966]

Well people will be inside the vertical Sunbed !

That is what the earth is for.

They are normally hard-wired, or use "commando" style plugs and sockets at that point so the earth/CPC should be reliable.

 

[Spike1947]

Yes it is hard wired, they also say use a class C mcb/rcbo !

 

[pc1966]

That would be C-curve trip characteristic in those cases, usually means a high switch-on surge.

• B-curve = 3-5 * In (rating current) for the "instant" magnetic trip
• C-curve = 5-10 * In
• D-curve = 10-20 * In

 

[Spike1947]

That would be C-curve trip characteristic in those cases, usually means a high switch-on surge.

• B-curve = 3-5 * In (rating current) for the "instant" magnetic trip
• C-curve = 5-10 * In
• D-curve = 10-20 * In

Yes , but why would a Sunbed need a C -curv as opposed to a B- curv and a 100mA trip as apposed to a 30 mA trip !

 

[pc1966]

Yes , but why would a Sunbed need a C -curv as opposed to a B- curv and a 100mA trip as apposed to a 30 mA trip !

The C-curve is probably due to the inrush current of the inductive starters for the UV tubes. The 100mA probably from having several of them each with some noise filtering.

If it is hard-wired and no issues with the cables being buried < 50mm then you don't need the RCD aspect. So if run in cable is definitely >= 50mm, or in trunking, or using SWA or (at lower currents) Flexishield for protection against penetration damage causing a shock risk, then you can just use the MCB.

Getting 3-phase RCBOs can be difficult, sometimes easier to have a MCB at the board and a separate RCCB for the RCD action.

 

[Taylortwocities]

You’ve already posted this on two other forums. Didn’t you like the replies on there?

 

[Spike1947]

You’ve already posted this on two other forums. Didn’t you

You’ve already posted this on two other forums. Didn’t you like the replies on there?

You’ve already posted this on two other forums. Didn’t you like the replies on there?

Is that a problem !

 

[Spike1947]

You’ve already posted this on two other forums. Didn’t you like the replies on there?

The above statement is from a pdf document, supplied by the Sunbed supplier, not from me !, attached is the full pdf.

cheers
Spike

 

[James]

Spec says. 63A rotary isolator must be fitted
Rcd is not required so don’t bury cable .

 

[Spike1947]

Spec says. 63A rotary isolator must be fitted
Rcd is not required so don’t bury cable .

RCD is going to be fitted just outside of the phase supply, am going to fit the rotary isolator at other end were it will terminate in the roomwere the bed will be located , then connect the sunbed direct to the rotary switch

 

[Spike1947]

Have decided it is not going to be within the house cicuit ( Blue phase) , am taking a feed from one of the phases ( Yellow phase ) in another part of the farm building, and putting it in a room within the farm building, where we have set up has a training/weight lifting etc room , the 3 phase feed to the farm is a TT system, there is several earth rods around the buildings .

Spike

 

[Zlodej]

Use the Contactum one not that Europa rubbish.

They are probably both made in a same Hong-Kong factory anyway
Strictly speaking I find Contactum more prone to fault then any other brand (Yes MK and wylex may give me most failed RCDs, but they are used far more often so that is natural). Although I find the paint from the otherwise well build Contactum metal box tend to start pealing within a first year in all four Contactum boards I have fitted.
There is the fact that the problematic MK main switch few years ago was made by Contactum and so where the series of problematic WYLEX RCDs (Which had a feature that if you push it less sensitively up, it stays on less sensitive).
I am not sure if it is any better then any other brand at all (maybe better then LVE). I am yet to find mine first failed chint MCB or RCD, yet I have seen quite few of their (mostly 3F) boards.

 

[Spike1947]

This is what I am thinking of putting in .

 

[James]

This is what I am thinking of putting in .View attachment 64721

You need to find an electrician
That is not a 63A rotary isolator
Nor is it a 100mA rcd

 

[Spike1947]

Rotary switch will be fitted in the room where the Bed will be located, then the Bed will be hard wired to that, am going to try it with a 30mA RCD, feel better with that protection than a 100mA .

 

[James]

The instructions tell you what supply is required
Also what protection to fit.

You seem intent doing it the way you want to.
You will not find someone here to back up your incorrect design.

I am unsure what further advice can be given.

 

[Spike1947]

The instructions tell you what supply is required
Also what protection to fit.

You seem intent doing it the way you want to.
You will not find someone here to back up your incorrect design.

I am unsure what further advice can be given.

Yes understand that, will get a 100mA if I can find one, can't see it been a risk using a 30mA , other than it will keep tripping if the leakage is as they say, read on this same forum posts fro 2018, where Electrcians are saying they put in 30mA RCD's and they have never had a problem with them tripping will feel better if 30mA will run ok , if not then will have to buy another RCD 100mA, prepared to do that .

 

[Spike1947]

Yes understand that, will get a 100mA if I can find one, can't see it been a risk using a 30mA , other than it will keep tripping if the leakage is as they say, read on this same forum posts fro 2018, where Electrcians are saying they put in 30mA RCD's and they have never had a problem with them tripping will feel better if 30mA will run ok , if not then will have to buy another RCD 100mA, prepared to do that .

S

 

[Spike1947]

The instructions tell you what supply is required
Also what protection to fit.

You seem intent doing it the way you want to.
You will not find someone here to back up your incorrect design.

I am unsure what further advice can be given.

So can you tell me what should be fitted, supply to the RCD will be via 25mm2 tails fed from the Main fuse board ( Not the DNO board they have 100A ) via a 80A fuse ! .

 

[James]

Find 2 local electricians
Give them each a copy of the installation instructions
Let them survey the site and quote accordingly

Ensure they understand that an installation certificate will be required for your liability insurance.

 

[Spike1947]

Find 2 local electricians
Give them each a copy of the installation instructions
Let them survey the site and quote accordingly

Ensure they understand that an installation certificate will be required for your liability insurance.

There is no
installation instructions

Find 2 local electricians
Give them each a copy of the installation instructions
Let them survey the site and quote accordingly

Ensure they understand that an installation certificate will be required for your liability insurance.

Why, it is not a commercial venture

 

[westward10]

You sat this site is TT so is there not already rcd fault protection in place. Why use an 80A fuse at the main board to feed another board when you could just fit the correct size of fuse at the main board.

 

[Spike1947]

You sat this site is TT so is there not already rcd fault protection in place. Why use an 80A fuse at the main board to feed another board when you could just fit the correct size of fuse at the main board.

Can't change them fuses at the moment, they have asbestos behind them, the whole board is going to be changed sometime this year ( NO not me ) it is quite old, and I doubt you will be able to buy any for that box now , yes there is a 3 phase 80A RCD with delay feeding the house and the farm, it is easier for me or a Electrcian just to put another unit from that fuse and it will give me a couple of more MCB's to fit at a later date if needed ! ( each phase has its own meter )

We had trouble awhile back with the main 3 Phase RCD tripping , then it was very difficult to locate the fault, now the House is on its own RCD and the Farm is split with a further 2 RCD's , the 8 way fuse box near the main fuse box is full, so it makes sence to have some spare ways to use at a later date !.

Spike

 

[MJPD29]

After reading this I am 100% certain you are not competent enough to do this job. Its time to call in a competent electrician. You haven't got a clue about any of the equipment your talking about, your asking incredibly basic questions, the terminology your using doesn't make any sense and personally i think your taking a massive risk doing this work yourself. Someone will be inside this, don't undermine their safety to save yourself a few quid.

 

[Spike1947]

The feed to the Sunbed is supplied via a 63A RCD , should there be more protection ?

 

[Spike1947]

And a 45A mcb