EWRB Electrical case studies
EWRB Electrical · Put your knowledge to work in context.
The Electrical Workers Registration Board (EWRB) is the New Zealand body that, in its own words, "promotes safety for all New Zealanders by ensuring the competence of electrical workers." Registration and licensing for electricians and other electrical workers sits with the Board, which is supported by the Ministry of Business, Innovation and Employment. Candidates reach registration through several routes - a New Zealand qualified pathway, a New Zealand experience pathway, a stepped pathway, an overseas-trained pathway and the TTMRA pathway for Australia - and each route requires evidence of competence, typically including theory examinations, a regulations examination and a practical assessment. The EWRB Electrical case studies are 5 cases and about 4,260 words.
1Workshop submain: the cable on the van is not the cable for the job
A registered electrician quotes to run a 230 V single-phase submain from the main switchboard of a house to a detached workshop. The route length is 65 m, including rises.
766 words, about 4 min2Arriving to find the earthing has been cut: what you can and cannot certify
An electrician attends a 1970s weatherboard house to install a new 20 A circuit for a heat pump. Before starting, they do a quick check at the main switchboard and find the main earthing conductor has been disconnected and taped back, the MEN link is present, and the earth electrode at the board is not connected to anything.
784 words, about 4 min3Detached workshop: MEN link, bonding, and what the builder's mate said
A 4-core 16 mm² submain is installed from the main switchboard of a house to a new detached workshop 35 m away, protected at the house by a 40 A MCB. The workshop has a concrete slab floor, a sink fed by a copper pipe that runs continuously under the driveway from the house, steel roof purlins, a 16 A socket circuit and a dedicated 20 A welder socket.
891 words, about 4 min4Isolating a pump controller with two supplies and a live PV array
A registered electrician must replace a failed contactor and thermal overload inside the controller of a 400 V three-phase irrigation pump on a dairy farm. The pump is fed from a switchboard 120 m away via a 63 A switch-fuse; the isolator has no integral lock and the fuse carriers are the only means of isolation at that board.
948 words, about 5 min5Nuisance tripping on a compressor circuit: bigger breaker is not the answer
A 20 A type B MCB in a domestic switchboard supplies a 2.2 kW single-phase compressor in a garage. The circuit is 4 mm² TPS, about 25 m long, and the MCB sits in a row of twelve in the same enclosure.
871 words, about 4 min