So like me you thought it was OK to plug a 10amp device into a 15amp outlet.

[aussiblue]

Like most people you probably all know you should not try to plug a 15amp device into a 10amp outlet or modify the cord or worse the plug so you could. But you also probably assumed like many, including me until today, that it was OK to plug a 10amp plug or device into a 15amp socket as they normally fit and appear to work fine. But I learnt today this is actually not the case.


I have a double 15amp outlet in my shed I had installed some years ago (when I bought my car lift) by an electrician with both separately fused so I could use both the car lift and a mig welder in my shed. I recently bought a Jamec Penn Wal Mounted tyre inflater to use with my Woodstar CP16 wall mounted compressor and decided that the most convenient place to hang this in terms of using it to fill tyres and to avoid having to use long extension cords or long hose lines was alongside the 15amp twin outlet and utilise that outlet with these two 10amp devices. However, when I came to plug them in I found that these 15 amp outlets were safety shuttered so that unless a 15 amp earth was in the earth pin socket access to active and neutral were blocked. Enquires to the Bunnings Workshop site about if suitable adapters existed initially resulted in advice that “I've spoken with HPM, and their HPM 15A Double Powerpoint will accept a 10A plug. Alternatively, it might be worth installing a 10A outlet next to your 15A” but subsequently the revised advice: “However, speaking with Deta, they have strongly advised that you do not force a 10A plug into their 15A socket as the shutters have been introduced to exclude 10A plugs; the reason is as follows: A circuit designed for 15A devices has suitable overload protection designed for them. It's best to run 10A devices on a circuit designed for them so the overload protection trips immediately if something goes wrong. A failing 10A device on a 15A circuit might not trip it immediately. If, for some reason, the overload is not triggered and the 10A cable or device overheats, it could be a fire risk.” On reflection this makes sense and so I guess it’s actually not really OK after all to plug 10amp devices into 15 amp outlets and I will be re-siting my wall mounted devices near one of the 10 amp outlets on the other side of the workshop.

Adding some more 10 amp outlets would be an expensive exercise for me as my existing switchboard is full so the last electrician I used said that if I wanted to add anything more it would have to be completely replaced or an additional sub- board added and, having been through that once to replace the original asbestos backed board, I know that gets to be a very expensive exercise that I cannot justify. I don’t really want 15amp cords or plugs on the inflator and compressor as that would prevent their use with normal 10amp outlets and void the warranty. For safety reason I also don’t want to suspend cords or air hoses over the top of my car lift. What I really need is a plug in safety switch that has both RCD and overcurrent protection; something like this but with 15amp pins: https://www.bunnings.com.au/arlec-si...witch_p7050029

In any event, I though other members would like to know about this little known safety issue. Most websites when I searched, wrongly it now seems, advise it is fine to plug a 10amp device into a 15 amp outlet.