April 14th, 2013
Have you had an electrician tell you that you HAVE to install a safety switch. I know that nearly every day I have to explain to customers that i have to install a safety switch in their switchboard to comply with AS3000/2007 standards. So I’m going to let you know where you can find the regulation at hand so you to can see that it is true.
The reg can be found as mentioned in AS3000/2007 at reg 2.6.3 titled: Where additional protection is required. I don’t intend on writing the whole reg as it would be lengthy but the key points state
- Additional protection by RCDs (safety switches) with a maximum rated residual current of 30ma shall be provided for final sub circuits supplying:
a) one or more socket outlets
b) lighting points
c) directly connected hand held electrical equipment
It goes on to say that this applies to pretty much all styles of installation be it domestic, commercial or industrial.
Of course there are a few exceptions but they are very limited and will very rarely apply in a domestic installati0n.
I personally think it is a great move forward to bring this regulation into action as I can honestly say it WILL SAVE LIVES!!!
Thanks for reading and any electrical question please ask away!!!
April 7th, 2013
Here is a lovely piece of work I personally came across the other day. The picture is of a nail that was put through a cable to fix it to a wooden stud. The reason I want to show this one is not to necessarily pick on whoever did it but to demonstrate how a lack of knowledge can really put people in serious danger when it comes to electricity. Its great to see people doing DIY projects around the house we all love to save a $$, but I too often see peoples attempt at DIY electrical and its 9.9/10 times completely dangerous or on the verge of becoming dangerous.The electrical trade is licensed for this very reason and i urge everyone to always use a fully licensed electrical contractor. In fact it is a legal obligation.
May 28th, 2012
If your house is protected by a safety switch, well done, you’ve done the right thing.
However you may need to know what to do if it’s triggered and more importantly, find out what caused it to trigger in the first place.
The key principle to this problem solving exercise is through the process of elimination.
The way a switchboard is usually setup, a single safety switch will protect many power circuits in your home.For example, you may have a separate power circuit for the kitchen, another for the laundry and a lighting circuit for the front of the house all of which are protected by the same safety switch. So when a safety switch activates, the first thing we need to do is work out which circuit is actually causing the problem.
Here’s 8 easy steps for how to handle a triggering safety switch.
- Turn all circuits associated with the safety switch off.
- Re-activate the safety switch. It should now remain activated, but if not you should call an electrician.
- Slowly, re-activate each individual circuit until one circuit causes the safety switch to trigger again. You now have identified the problem circuit.
- Turn off all the circuits again, and now turn them all on except for the problem circuit.
- Go around your home and try to find where the power is not working e.g. the kitchen. These will be power points associated with the faulty circuit. A good place to start is always fridges, microwaves, motors, pumps.
- Unplug all the appliances that are connected to the faulty circuit.
- Once you are certain ALL appliances are unplugged from the circuit, go back to switchboard and re-activate the faulty circuit. It should now all stay on and not trigger again. If it does still trigger, call an electrician. You now need to eliminate appliances until you find the one causing the problem
- One by one, plug each appliance back into the power point. Eventually one of these appliances will cause the safety switch to trigger. Congratulations, how have now identified the faulty appliance. You can get your appliance repaired by an electrician or replaced.
Now you should feel confident the next time your safety switch goes off that you know how to find a problem. Hopefully you’ve found this article helpful!
Keith, the sparky.
April 3rd, 2012
Have you ever been told you need a Safety switch installed in your home or business, and wondered why? or how it works? Well in this blog I aim to explain both for you. Hopefully in a clear and simple manner.
Why is simple, it is in the name, it is for SAFETY, it is the one device that has in my opinion really moved electrical safety forwards. It protects you and your loved ones or employess.
To understand how a safety switch works firstly you need to understand the way electricity is transported throughout your home or business. Electricity is transported through wiring and it nearly always consists of 3 cores being Active (red), Neutral (black) and Earth (Green).
In a basic description:
- Active: sends the electricity
- Neutral: returns the electricity
- Earth: connects to any exposed conductive surfaces, to offer a first line of protection
In a normal state of function all electricty sent by the active must return in equal volume via the neutral.
So now that we know that, how does a safety switch work?
A safety switch utilises both the active and neutral cores and heavily relies upon the earth but it is not mandatory to its funtionality. A safety switch is a monitoring device that can measure the flow of sent & returned electricity through the neutral and active cores, as explained earlier in a normal state this will alays be equal. The device that monitors this is called a differential current transformer it is found withing the workings of the safety switch.
1. differential transformer
2.differential transformer windings
3.Differential transformer core
4.A test switch (this should be activated monthly, and can be pressed by you, however if it does not activate your safety switch call your electrcian straight away)
What makes the device activate?
The device will disconnect all power to its circuit when a inbalance is detected within the differential transformer (so if the sent electricity does not equal the retunred electricity). What may cause this imbalance can be numerous things all of which can be dangerous to living creatures. I will list a few causes and try explain further.
You have a clothes dryer that has a metal casing, so therefore it should be earthed for safety. A active cable inside the workings of the dryer comes loose and touches the metal casing. In this state the electricity will be sent through the active but return via the earth, causing an imbalance in the transformer and activating the safety switch.
You have your nephew over and he is very inquisitive and decideds to stick a knife into a socket outlet!!!! If a safety switch is installed it will detect that some electricity is not being returned via the neutral but rather it is going through your nephew and will automaticall shut off within .4 of a second. In this case the human recieves a electric shock but it is for a much shorter period than fuses, and in some cased a fuse wont even shut off, it will continue to send power.
You are doing some renovations and decide to cut through a wall with your saw, but unknowingly you cut straight into a power cable. As you cut through an inbalance would be detected in the safety switch as a small amount of electricity will pass through you and once again the safety switch will disconnect the power within .4 of a second.
So looking at these example you can see why the earth is so important as it takes the electrical shock instead of a human. Compare example 1 to example 2. Please note though that Safety switches are not a gurantee there are some situation where they do not work. Caution should always be applied around electricity.
- Safety switches are great for improving the electrical safety of your house or workplace
- It works on detecting an inbalance in electrical flow
- They are not a gurantee but in the majority of cases they will save lives
- Always test your safety switch
I hope this has been informative, and shortly i will discuss what to do if your safety switch activates
0419 586 730