It is tragic that an elderly couple and their son were electrocuted because a water heater at the couple's home had been installed in an unsafe manner (Water heater in electrocution case installed in unsafe manner: Expert, March 10).

The Straits Times' report included details on the risks that ageing flats may pose due to dated electrical workmanship and natural degradation of cables.

The expert from the Energy Market Authority (EMA) said a water heater should be connected to a double-pole switch instead of a wall plug. Investigators also found that the cables in the water heater's plug had fused together.

I searched the Housing Board and EMA websites and found some pictures and diagrams that illustrate what the expert said.

Besides HDB flat dwellers knowing what the correct double-pole switch for a water heater looks like, should they also check if the cables in the plug have fused if the water heater is connected to a socket?

According to investigators' findings, a metallic water hose connected to the tank may also have been a key element in the electrocution. Should non-metallic water hoses be used instead?

There are still many old flats in Singapore. If residual current circuit breakers were installed in these flats later, is only partial protection provided as was the case in the couple's home?

Can HDB look into some kind of audit for ageing flats?

Tan Kar Quan