Octopus installed a smart meter for us… the cost of making a cup jumped from 1p to £5 overnight

Boiling the kettle for a cup of tea sent Ford and Ann Jones into a panic when their newly installed smart meter showed it was adding £5 to their electricity bill.

To make sure their eyes weren’t deceiving them, they tried out the washing machine – only to find they were being charged £15 to wash their clothes.

They called their utility company, Octopus Energy, to try to find out why their bills had suddenly jumped after installing a smart meter a few weeks earlier.

Before then, boiling the kettle would only add about a penny to their bill. At first, the energy supplier ignored their pleas.

It was only when they contacted the independent engineer who fixed the solar panels to their roof that he noticed the ‘CT clamp’ had been re-connected the wrong way, causing the meter readings to ‘crack’.

Experts believe that this is not an isolated incident. One electrician says he was called a dozen times last year because smart meter installers rewired existing solar panel connections the wrong way.

This CT clamp is a ‘current transformer’ the size of half a matchbox that is placed over the power wires that go into the smart meter and measures the current going in and out.

They are sometimes supplied with arrows printed on the terminal – but this is difficult to read for anyone but an electrician.

In numerous phone calls since their smart meter was installed last February, the retired couple in their 70s have been told to ‘ignore the meter’ and that ‘the meter could take a few weeks to settle’.

This was despite being billed £3,000 over a three-month period – more than ten times the usual quarterly bill.

Ford says: ‘Octopus told us not to worry – but that didn’t stop them from still sending much bigger bills.’

The couple downsized to their modest three-bedroom bungalow two years ago and installed a dozen solar panels on their south-facing roof in a bid to protect themselves from rising energy bills in the future.

Octopus Energy claimed the smart meter installed last February will monitor their energy usage – and hopefully help cut costs by showing them how they’re saving electricity.

Ford adds: ‘It was only after I logged on to Octopus’ website and showed proof that our energy consumption had skyrocketed after the meter was installed that they finally paid attention.

‘But it wasn’t until August that we managed to get an engineer to fix the problem.

‘I insisted Octopus fix the CT clamp because if I had got another engineer to do the job, the energy supplier could have said it wasn’t their fault.’

And Dave Cookman, a professional electrician with more than 20 years experience on electrical installations – including solar panels – believes their experience is far from unusual.

Dave, owner of D Cookman Electrical in Dunstable, Bedfordshire, says: ‘This problem of people installing smart meters when they already have solar panels is becoming more and more common. In the last year alone, I had ten similar cases.

‘These clamps measure the flow of electricity using magnets.

Get the clamp back the wrong way, which often happens with smart meters installed by people who aren’t tech-savvy, and the reader suddenly has no idea what’s going on – and could start telling you anything other than your rightful use.’

He adds: ‘It is understandable that energy suppliers such as Octopus do not want to admit responsibility.

‘My advice is to contact your installer straight away and insist they come out and fix the problem if your energy bills go up unexpectedly after you’ve agreed to have a smart meter installed at your home.’

The couple were compensated by Octopus after Money Mail intervened and admitted an engineer had reinstalled their CT clamp incorrectly.

Octopus said: ‘We install thousands of these clamps a year, and it’s a very rare mistake, which meant some of our team didn’t pick it up as quickly as we would have liked.’

If you have been affected by wild smart meter readings: toby.walne@dailymail.co.uk