On Thursday, February 9, 2017 at 3:10:34 PM UTC-5, James Wilkinson Sword wrote:
We are given 230V +/- 10% (not sure of the exact percentages). Unless it goes outside that, they are not obligated to do anything. It appears they recently fitted a new transformer presumably to cater for higher usage, which is currently running nowhere near full capacity, and therefore over voltage.

Transformer increases or decreases voltage to adjust for varying loads. These adjustments occur many times daily. That is a less than 10% (acceptable) variance. If voltage cannot be maintained (if too high or too low), then utility equipment disconnects power to protect consumer appliances.

Concern is for voltages so high (and short) as to cause damage. So protection is installed both by the utility and by a consumer using a properly earthed solution. Defined are the two layers of protection.

Every protection layer is only defined by an item that does protection - earth ground. A protector without earth ground is not a layer of protection.