Professional Property Maintenance

ISOLATE before you INVESTIGATE

DANGER OF THE WEEK AWARD

Cowboy Heating Engineers

Always ISOLATE before you INVESTIGATE. Why? As shown in this weeks photo the heating engineer decided that running 240 volt down an earth cable was acceptable. What’s that mean to you?

The other end of this cable was terminted about a half metre away. This ’shocking’ hookup was down to lazzines and the engineer didn’t care if the next person along got zapped!

Fortunately, the next person along was us. Unfortunately, a lot of home owners have only basic knowledge and might have assumed incorrectly that the green/yellow cable was earth. In this case it was live, VERY LIVE!

The general rule is to isolate before we investigate. I like that! ISOLATE before you INVESTIGATE. When troubleshooting however we will leave the circuit energised while checking voltages as certain points in the circuit.  What we originally saw was the other end of this earth wire connected in a poorly wired junction  box and noticed it was hooked to a live feed from the central heating controls. When we followed it back to the cylinder thermostat we found the problem shown above. In case you missed it, the centre wire (green/yellow) is hooked to a live connector.

The tank thermostat is used to open and close the heating circuit. In general terms, all of the wires on the therostat will eventually be carrying 240 volts through them. There should have been three wires and an earth in order to comply with the building regulations and wire it safely.

NEVER use an earth to carry voltage. No excuses. Never do it! And NEVER assume that a circuit is wired safely. ISOLATE before you INVESTIGATE!