A Wellington plumber has been fined $4500 at the Porirua District Court, following investigation into work carried out in Westport.
Michael Guy pleaded guilty to one charge of carrying out sanitary plumbing in a manner dangerous to life and two charges of carrying out sanitary plumbing without authorisation.
In one case, a hot water cylinder he'd installed blew up.
The Plumbers, Gasfitters and Drainlayers Board said Guy had failed to have his supervisor check his work at two Westport homes where he worked on hot water cylinders.
The jobs included installing a tempering valve onto the open vent line of a hot water cylinder connected to a wetback.
"The work did not comply with regulatory requirements ..." the board said in a statement.
"Non-compliant work of this nature creates a health and safety risk to the consumer and could result in implosion or explosion and serious injury.
"In one case the hot water cylinder did implode as a result of the tempering valve installed."
Guy had reimbursed the property owner for the damaged cylinder, the board said.
Its chief executive, Max Pedersen, told the Westport News the offences happened in 2011 and 2012.
Guy's supervisor was his father, Barry, who was from the Wellington area at the time. Michael Guy had been a plumber since 2003.
He holds a current plumbing authorisation but is no longer living on the West Coast, Mr Pedersen said.
There were serious health and safety risks associated with sanitary plumbing carried out by someone working outside the limitations of their authorisation.
All authorised tradespeople were required to carry an authorisation card.
Consumers could check to see if a plumber, gasfitter or drainlayer was authorised to carry out the work, and the limitations of authorisation classes, by logging on to the board's website at www.pgdb.co.nz.
A homeowner could contact the board if they had concerns about a tradesperson.