Our overalls have orange panels and reflective stripes, designed to provide maximum visibility - day and night. The colour layout complies with Transit NZ standards so when our people are working on the road they do not need to wear day glow jackets over their overalls.
Site Traffic Management
One person has to be in charge of traffic control. That person decides on the positioning of signs, cones and barriers and is called the STMS (Site Traffic Management Supervisor). The STMS has to be easily spotted out of everyone on site, so is required to wear a yellow day glow jacket.
Six monthly refresher safety course
All Northpower employees who work in the field learn first aid, CPR, emergency rescue and safe work practices. They have a refresher course in all these skills every 6 months and get very good at it. If you have an accident, you would be lucky if a Northpower worker was around, because he (or she) would know what to do.
Hard Hats stand up to the test
Hard hats are put through some very tough tests before they are approved for use in New Zealand. This is what they do to see how tough they are:
- A 4 kg steel ball will be dropped several times from a height of 15 metres. The hard hat is passed if there is no damage.
- A variety of acids, gases, solvents, oils, and industrial gases are applied to the hat. It must pass with no deformities or obvious color change.
- To determine fire resistance, the hard hat will be subjected to a propane torch for five minutes.
- The hat must sustain 2,200 volts AC, 50 Hz, for three minutes.
A hard hat that can withstand this amount of punishment will provide an amazing amount of protection to the person wearing it.
Fireball can reach nine thousand degrees
Sometimes short circuits occur on electrical systems while our people are working on them. In the worst situations there is a loud bang and a fireball that shoots out from the equipment. The fireball temperature can reach nine thousand degrees but for a very short time. If a person's bare skin is hit by that arc it will be severely burned. The overalls our field workers wear protect the person but they will still get very hot and the worker's skin may have slight burns. Enough heat can pass through to the next layer of clothing to melt it if it is made of synthetic material. For this reason it is advisable to wear cotton underwear because cotton will not melt.
Our Tree Cutters use techniques similar to abseiling
Our Tree Cutters are trained in climbing techniques similar to abseiling or mountain climbing. They use the same types of ropes, and attachments. The most common attachment is a caribiner which is like a very large safety pin. It is important that the caribiner should not be able to open accidentally by pressure from branches the tree cutter is working close to. If it did open, the rope holding the tree cutter to the tree could be released and he would fall. That is why the caribiners we use have triple action locks. You have to lift the locking piece up and unscrew it before the latch can be pressed in to release the rope.
Gloves are insulated to 40,000 volts
Our most skilled Line Mechanics can work on lines up to 33,000 volts while they are still live. They wear gloves that are insulated to 40,000 volts. The gloves are quite thick and they reach up to the workers elbow. Gloves have to be carefully examined before they are used each time. Even a tiny pinhole in the glove can make them useless because the hole would allow current to pass right through them. To check a glove, the line mechanic will roll it up tight so the hand and fingers puff up like a balloon, and then he will check to see if there are any leaks. Every 6 months the gloves are given an electrical test to prove that they can still withstand their rated voltage.
Glove and Barrier work
Our live line workers use elevating buckets to get up to the lines. The buckets and the boom that raises them are insulated to 56,000 volts. They also have a protective liner to increase the safety, which is insulated to 70,000 volts. When a line mechanic is in the bucket, he is insulated from the ground and when he touches the line, he is like a bird that perches on it. As long as he does not touch two lines at the same time, he is safe. He will take covers up in the bucket to put over the lines he is not going to work on so that he will not accidentally touch two lines at once. He will have other covers to put onto the pole and the crossarm so that everything is covered up except for the one line that he needs to work on. When he has finished work on that line, he will put covers on it and take them off the next one. The covers are called Barriers, so the technique is called "Glove and Barrier" work
Using a spiking gun
Underground lines are difficult to identify because you usually can not see where they come from or where they go to. If we need to work on a high voltage cable, we do not just cut into it, because if we have picked the wrong one and it is alive, there will be an explosion when the knife hits the live conductor. Anyone near that explosion could get hurt. For this reason, we have a spiking gun. This is a clamp which we fix around the cable. Attached to the clamp is a spike, which is driven into the cable by an explosive charge. The charge can be fired by someone who is well away from the cable by pulling a string which is attached to the firing trigger.
Northpower employees are encouraged to report any near misses or hazardous situations. We take this information and look for ways to make the job safer. Research has shown that if a group of workers is having a lot of near misses and minor accidents, there is a serious risk that a major injury will occur. A man called Heinrich developed a triangle which shows that on average, 300 no injury accidents will lead to 29 minor injuries and one serious injury.
By always looking for ways to make our work sites safer, we can reduce the number of close calls, minor injuries and - most importantly - serious injuries.