Power Shower Tripping Rcd

[r6kev]

Hi guys

I have a customer with a Mira Vigour power shower (hot and cold water feed, & 1.5mm T&E elctrical supply via an inline stand alone rcd)

He says it was all fitted as part of his bathroom refurb just 18 months ago.

Recently he kept coming to it and finding it had no power. He's an OAP, and the RCD has been fitted in the loft, above the shower, so he called me in the first instance. I reset the rcd 3 times in as many weeks.

I disconnected from the rcd, and did an insulation resistance test (between L and earth, and between N and earth) firstly on the cable alone, then on the cable with the shower unit connected. All seemed fine, (>299 ohms).

So I replaced the RCD (less than 20 quid), All was fine for a week, then the new RCD tripped..!

I went back today and retested the cable alone, then the with the shower unit connected (with the dial turned on to activate the microswitch), and again all results were >299 ohms..

My test results and my logic are saying it must be an earth fault on the shower unit once it's been running..

But, it's only 18mths old, it's a very reputable brand, and it's £240 to buy a new one so I don't want the poor old buger wasting that kind of money on my say so! Also he says it never cuts out while he's using it, it's just periodically dead when he comes to it..

so, duff shower unit, or other cause?

Thanks for your ideas guys,

Kev

 

[Robin Spark]

Have you taken the cover off the shower to look inside?

Do you have a leakage clamp meter so you can check the actual leakage whilst the shower is working?

I had a power shower that had carbon dust all inside the casing that was causing interfernce to my TV.  Once it was cleaned out this all stopped, not sure if this would affect an RCD though?

 

[r6kev]

Yes, had the cover off to disconnect for testing..

Looks brand new inside..

This is why i'm a little reluctant to assume it's the shower unit.. The old boy only uses it 3 or 4 times a week as he like to have baths too, so it hasn't exactly had a hard 18 months either!

 

[SPECIAL LOCATION]

By power shower???

I assume you mean a shower with a booster pump somewhere in the flow pipes?

Is it a pump related problem rather than a shower unit problem??

If it is faulty and was installed 18months ago as part of a bathroom refurb.....

Who did the bathroom refurb?????

Surety it is their problem to solve under warranty???

 

[r6kev]

Yes, it's basically a mixer tap and a variable speed pump in a nice looking box! Looks like a electric shower though!

And the Mira guarantee is only 12 months.. Which i thought a bit poor for something costing £240!

 

[SPECIAL LOCATION]

Yes, it's basically a mixer tap and a variable speed pump in a nice looking box! Looks like a electric shower though!

And the Mira guarantee is only 12 months.. Which i thought a bit poor for something costing £240!

but sale of goods act 1979 and supply of goods and services act 1982..

state that ALL  goods and services MUST be fit for purpose and of merchantable quality..

These give certain legal obligations to the suppliers and manufactures of items that exceed 12months when it can reasonably be expected that an item should last longer than 12months.

Who actually installed the shower???

I would be contacting them first.

 

[r6kev]

The original installers have apparently ceased trading according to the customer..

I like the sound of those Acts, they sound like common sense prevailing!

That assumes it is actually a fault on the Mira shower, which at the moment I'm not sure i can prove!

 

[Evans Electric]

I was about to say the pump could be the suspect ..then noted you said the RCD has tripped when he first comes to use shower , so probably not a pump problem .

Nothing much in the shower itself to cause a problem is there? 

Sometimes I've known other stuff cause tripping of a RCD   and one famous incident of mystery tripping that was caused by the front door being slammed shut .      If you tapped the device lightly with driver ...it tripped  !!!  Crabtree Starbreaker.  Replaced and all was tickety - boo . Whatever that means.

 

[NozSpark]

Just thinking......

Is there anyvway you could fit a DP pull switch between the RCD and shower and get your customer to isolate it when its not in use????

It'd at least help you with your investigations

 

[ProDave]

At the risk of asking the obvious, was the shower switched ON when you did your IR tests?

If not, then you won't have been testing the internal wiring and pump etc.

But do open it up, there might be something obvious like water has got inside.

IR test the pump directly with the covers off.

 

[NozSpark]

At the risk of asking the obvious, was the shower switched ON when you did your IR tests?

If not, then you won't have been testing the internal wiring and pump etc.

But do open it up, there might be something obvious like water has got inside.

IR test the pump directly with the covers off.

It may not matter.... the function of the shower might not put the pump in circuit without the power being on and water flowing

 

[m4tty]

I was thinking is there an isolator fitted and the client has been using it which is one of them beauties that disconnects line and neutral at slightly different times which the rcd sees as an imbalance ? Just a thought