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bwal74
12th Jan 2019, 08:19 PM
Hi,

I think I know the answer to my question but I'll ask it anyway.

Is it possible to have a 15 amp female plug with a 10 amp male plug extension cord? I only ask as Bunnings has a special on a welder that is 15 amps and while I figured it I could put in a 15 amp power point but what happens if you go somewhere or need to work outside and you need an extension cord?

Ben.

BobL
12th Jan 2019, 08:59 PM
Interesting that you cannot usually buy such an extension cord but you can of course make your own up - I have several with a built in ammeter so I can monitor the current being drawn.
They're not considered legal so if you burn your house or shed down and it is found to be the cause of the fire you won't be covered by insurance.

However you can buy a "legal" product that do this but restrict the current throughput to ~10A.
https://www.bunnings.com.au/hpm-15a-single-outlet-power-convertor-with-rcbo-protection_p7050100
The built in breaker nominally triggers at 10A so if your welder draws more than this for too long it will.
Repeated trips can become a PITA.
If you are only welding light weight material it should still be OK.
Note: Not considered suitable for caravans or building sites.

I made my own for about $40.
http://metalworkforums.com/attachment.php?attachmentid=373045&d=1525007368
See http://metalworkforums.com/f309/t201752-15amp-mig-welder-plug-10amp-wall/page-2#post1934498

KBs PensNmore
12th Jan 2019, 09:10 PM
*** Disclaimer - any information provided should be viewed as for entertainment purposes only and should not be used as replacement for advice from a licensed electrician ***


Hi Ben, It's a doable thing, not legal, so don't get caught with it.:rolleyes: I'd use a 15amp cord, as it'll handle the welder OK, what happens after that is up to you. If the cable is long, don't use it coiled up, as it'll get hot and create problems. Work out what your usual lenth would be and get a cable to suit, or lay the cable out in an "S" shape to use it up.
Regarding the Bunnies welder, some of those welders are a bit on the cheap side, so don't expect too much from it.
Watch the duty cycle, sometimes they are quite low, meaning that you weld for 5 minutes and wait 30 minutes for it to cool down.
Kryn

simonl
12th Jan 2019, 10:20 PM
If you are going to go to all that trouble making an illegal extenion cord then you may as well just change the plug on the welder to a 10A plug! You can still connect it to a 15A lead and plug it into a 15A PP.

However, the whole idea of a 15A PP is to ensure it is able to take 15A. If you plug the welder into a 10A GPO then how can you ensure you won't melt the wire inside your walls?

Simon

Com_VC
12th Jan 2019, 11:32 PM
If you are going to go to all that trouble making an illegal extenion cord then you may as well just change the plug on the welder to a 10A plug!

Only problem with that is you would void the warranty on the welder.

I've worked in work places before where a short lead say 200mm long with 10A plug on one end and 15A on the other was made for this very purpose.

bwal74
13th Jan 2019, 07:17 AM
Cheers Fellas,

IRT the cheap welder, I know you only get what you pay for. Their cheap Boss welders aren't too bad if you only want something for hobbies and such.

I can't burn down my parents house though, that'd be pushing the boundaries of love.

Ben

.RC.
13th Jan 2019, 07:55 AM
However, the whole idea of a 15A PP is to ensure it is able to take 15A. If you plug the welder into a 10A GPO then how can you ensure you won't melt the wire inside your walls?

Simon


You go by the size of the fuse on the circuit. After all you can buy wall mounted GPO's with four 10 amp sockets on the one board connected to the one cable. If the wiring was an issue then the very strict electrical rules would never ever ever allow any more then a single GPO per circuit.

Grahame Collins
13th Jan 2019, 08:00 AM
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Updated by Grahame - 13-01 -19

Grahame Collins
13th Jan 2019, 08:17 AM
If the wiring was an issue then the very strict electrical rules would never ever ever allow any more then a single GPO per circuit.

In regards to a legally installed 15 amp GPO, this is what occurs at least in Queensland. I asked about twin point switches when the sparkies were installing 15 Amp GPO's in my shed.

No! there is one single point switch per circuit.

Perhaps sparkies from the other states would care to confirm this?

Grahame

BobL
13th Jan 2019, 09:22 AM
In regards to a legally installed 15 amp GPO, this is what occurs at least in Queensland. I asked about twin point switches when the sparkies were installing 15 Amp GPO's in my shed.
No! there is one single point switch per circuit.
Perhaps sparkies from the other states would care to confirm this?


My understanding is it's up to the electrician's discretion to make a proper assessment of the proposed usage of the GPO, same as they are supposed to think about the size and type of breaker they use.

They are also supposed to do this on 10A circuits but given the number of 10A GPOs the sparky installed on the 10A circuits in my shed and house I do wonder how many actually do this. Except for the stove, every appliance in our kitchen is on the same 10A (16A breaker) circuit installed as part of the house extension some 20 years ago and I remember discussing the electrics with the sparky and he reckoned one circuit would be fine. They bank on the fact that even though all these appliances are switched on they assume they will not all be under load at the same time. However, when the fridge, freezer, dishwasher, microwave, coffee machine (draws ~9A under the 1:8 heating cycle) and the electric kettle are all on, the breaker would trip. When I complained to the builder he sent the sparky around and all he did was installed a breaker that took slightly longer to trip!

With 15A circuits it's just easier for them to say "no" probably so they don't have to think too hard about it

In my shed have my VFD powered 4HP wood dust extractor and welder on the same 2 point 15A GPO but I never run both at the same time as I have welding and grinding fume extraction on a separate 10A circuit.

Same with my 4HP WW BSander and 3HP WW Bsaw which are both on VFDs so they have a don't have high start up currents (~7A).
I even leave them running (not use - there is only one of me) at the same time as they only draw about 1A when free running.
It's very difficult to get either machine to draw more than about 10A under load so the breaker just never sees 15A

The other 2 point 15A GPO is used to test motors and run a (10A) washing machine outside a shed. The washing machine is not used when testing motors.

I realize these are slightly unusual situations and not everyone is capable of analysing their setup in this level of detail but it shows what can be done safely with a bit of care.

RustyArc
13th Jan 2019, 10:16 AM
In a correctly-wired house, there should be no risk of internal wiring burning up no matter what you do at a power point. The breaker is sized to protect the internal wiring.

So the issues arise at the power point and beyond. It could be argued, for example, that a 10A power point's conductors aren't designed to carry 15A. The fact that the current-carrying pins on 10A and 15A plugs are the same dimensions indicates this may not be a problem, but you can't say for certain.

The reality is that the most common consequence of inappropriate load, whether it be a big-arsed welder or just an electric jug and blow heater on the same circuit, is nuisance tripping.

As an aside, I remember seeing a foot-long 10A plug to 15A socket adaptor lead on a coffee machine that had a test tag on it :)

Grahame Collins
13th Jan 2019, 12:22 PM
I've worked in work places before where a short lead say 200mm long with 10A plug on one end and 15A on the other was made for this very purpose.

If or when a WH&S inspector walks in an finds this in the course of their duties, then such places should prepare for a big fine.
It does not matter a whit whether the cable has worked flawless or has not caused a fire or fatality, someone, will be in deep do do.

Along with prosecution given that an incident occurred goes a loss of potential insurance claim if any damage occurs.

In the meantime, we as DIYers tell the whole bloody world about what we do electrically speaking knowing full well it is illegal.
Do any of you think that perhaps people like insurance adjusters or the like, might also be DIYers and follow the electrical threads out of interest?

You should be able to see where it could go from there should one of you be unlucky enough to have an electrical incident.

Grahame