Overvoltage powersupply blowing up microwaves!

raven_r

In 2 years we have had 3 microwaves blow up. I have measured the mains supply voltage and it's well over 240v but not over the 'official' 253v +10% overvoltage limit. Any suggestions on how to go about a) getting Northern Powergrid to reduce the voltage, b) getting them to pay for the damaged equipment c) any other measures I can put in place to stop the mains killing microwaves? This is getting expensive!

System

If its not outside the limits then there is very little that you can do

raven_r

248v this evening...

malc_b

According to this in the UK the statutory limits are 230v-6% and 230v+10%. This translates as 216.2v to 253v. The problem might be more that the microwaves are not meeting UK spec but are more designed for 230Vac rather than 240Vac. If the supply is within the legal limit then it's the microwave makers fault.

Andy_WSM

raven_r wrote: »

248v this evening...

The supply is often at 250V here, more so on sunny days due to all the Solar PV on the estate. I've not encountered any failures of equipment and anything you buy in the UK should be able to cope with AT LEAST the 253V allowed maximum (230V +10% / - 6% tolerance)

matelodave

We get 245-248v on most days and so far nothing has blown up or died so I'd suggest that you must by buying out of spec microwaves. Unless you can get a monitor/recorder put on your line to check for transient over voltage there's not much you can do

Ich_2

I think you will have to do better than seeing an effect adding 2 and 2 and getting a possible answer.
To have any chance you would have to have them examined by an independent electronics engineer to find/prove the cause of failure.

As the voltage is within the legal (UK & EU) limits it is very unlikely the voltage is the cause unless the microwaves don't meet the required specification.

A recent case I'm aware of saw voltages up to 259 with no detriment to electronic devices.

Ich_2

The full range of voltage that can be found throughout the EU is 207 to 253.

Most of mainland Europe used 220V whilst the UK used 240V
When it was standardised to 230V different allowable variations were brought in.
The UK being 230V +10/-6% as previously stated
Most of the rest are 230V +6/-10% which covers the voltages normally found in those countries.

So any equipment sold to operate in the EU must be able to operate over those ranges, a lot isn't