Triton enlight trips out

[pinn73]

Hello,

Recently after running the shower for 5 mins, it trips out . If I reset it via the fuseboard it will again run for a few minutes before the same happens again.

I'm a little concerned re. the safety of this so any advice would be greatly appreciated.

Thanks

 

[JohnD]

how long have you had the shower?

what is its rated power?

What is printed on the thing that trips? (all the letters and numbers please)

 

[pinn73]

The shower was in when we moved so unsure of age.

Google says it's 9.5kw

I've attached a pic of the switch which keeps tripping.

Thanks

 

[JohnD]

It's a 40Amp shower on a 32Amp breaker, so of course it is tripping. It's overloaded.

The cable may also be too thin to carry 40A without overheating.

This often happens when somebody replaces an electric shower with a more powerful one without understanding.

 

[pinn73]

Previ

It's a 40Amp shower on a 32Amp breaker, so of course it is tripping. It's overloaded.

The cable may also be too thin to carry 40A without overheating.

This often happens when somebody replaces an electric shower with a more powerful one without understanding.

Previous owner must have I guess. Is it possible to put a 40Amp breaker in place of the 32a one?

 

[JohnD]

The cable may also be too thin to carry 40A without overheating.

You need to get a qualified electrician in to examine the cable and the route it takes.

 

[JohnW2]

It's a 40Amp shower on a 32Amp breaker, so of course it is tripping. It's overloaded.

The 9.5kW is probably quoted at 240V, which would equate to about 37.9A at 230V.

A B32 should never trip at below about 36A (32A x 1.13), and would trip within an hour at about 46A (32A x 1.45). Indeed, the curve for a B32 in the regs shows it never operating at 40A, at least, not within the first 10,000 seconds (about 2.8 hours).

I am therefore far from convinced that the OP's RCBO is tripping 'in minutes' due to the OPD part of its functionality.

Kind Regards, John

 

[pinn73]

The 9.5kW is probably quoted at 240V, which would equate to about 37.9A at 230V.

A B32 should never trip at below about 36A (32A x 1.13), and would trip within an hour at about 46A (32A x 1.45). Indeed, the curve for a B32 in the regs shows it never operating at 40A, at least, not within the first 10,000 seconds (about 2.8 hours).

I am therefore far from convinced that the OP's RCBO is tripping 'in minutes' due to the OPD part of its functionality.

Kind Regards, John

It worked fine for a couple of years until the past few weeks when it exhibits the behaviour I mentioned.

To your point, isn't that working on the assumption that the cabling is sound? I'm going to get someone in to test it.

Thanks for all your advice

 

[JohnW2]

It worked fine for a couple of years until the past few weeks when it exhibits the behaviour I mentioned.

That's consistent with what I just wrote. Even though one shouldn't overload a device (like your RCBO) 40A through a 32A RCBO should not trip in minutes. So, either something has happened to the shower or the RCBO as become faulty; the former would seem more likely.

To your point, isn't that working on the assumption that the cabling is sound? I'm going to get someone in to test it.

I very much doubt that anything has happened to the cable to cause what you are now experiencing. The reason you need the cable inspected and tested is to determine whether it is adequate to support an upgrade to a 40A or 45A RCBO (which is what you should have).

Kind Regards, John

 

[stillp]

An MCB that's been intermittently overloaded for "a couple of years" might no longer be within spec, so it could now be tripping at a lower current than expected.

 

[JohnW2]

An MCB that's been intermittently overloaded for "a couple of years" might no longer be within spec, so it could now be tripping at a lower current than expected.

That's certainly a possibility, even though the degree of overloading is not all that great.

As has been said, the important thing for the OP is that he should get the wiring checked by an electrician to see it is suitable for upr-rating the RCBO to 40A or 45A, so that he can hopefully avoid continuing to run with an overloaded (even if only a little) device in the future.

Kind Regards, John

 

[winston1]

The 9.5kW is probably quoted at 240V, which would equate to about 37.9A at 230V.

A B32 should never trip at below about 36A (32A x 1.13), and would trip within an hour at about 46A (32A x 1.45). Indeed, the curve for a B32 in the regs shows it never operating at 40A, at least, not within the first 10,000 seconds (about 2.8 hours).

I am therefore far from convinced that the OP's RCBO is tripping 'in minutes' due to the OPD part of its functionality.

Kind Regards, John

What makes you think his supply is 230 volts? Whenever I have measured mains at various places in the UK it is around 242 volts.

 

[JohnW2]

What makes you think his supply is 230 volts?

Nothing, but electricians conventionally undertake their calculations on the assumption of 230V (even when determining whether something is 'overloaded'), regardless of what the supply voltage might actually be.

However, what matters here is not the 'supply voltage' but the voltage at the shower - and, particularly in the case of 6mm² cable, that is usually going to be a good few volts lower than the supply voltage - so probably usually closer to 230V than 240 in many/most UK houses.

Kind Regards, John

 

[ban-all-sheds]

What makes you think his supply is 230 volts?

What makes you think that calculations should be done in a way which contravenes the regulations?

 

[JohnW2]

What makes you think that calculations should be done in a way which contravenes the regulations?

I doubt that anyone would worry of a 'contravention' which was more conservative/'safe' than the regs actually require!

I suspect that the authors of the regs have never really thought this one through, in the same way that it took them many decades to introduce the concept of Cmin (for circuit protection) which appeared only a couple of years ago. Prior to that, a substantial proportion of properties probably had electrical installations which, although compliant with regs, did not actually satisfy the requirements for fault protection.

Returning to the original point, logically speaking the considerations of OPD ratings and cable protection should really be based on the 'worst case' assumption of a maximum permissible supply voltage (i.e. currently 253V in UK).

Kind Regards, John