Can I draw 20A from a double wall socket?

Forums › Home Workshop DIY › Can I draw 20A from a double wall socket?

1 | 2 | 3

280 posts

Ultimate Geek
+1 received by user: 134
Inactive user

#2279110 18-Jul-2019 15:54

I am familiar with USB chargers, but they have nothing to do with this conversation. No-one has offered any proof of this statement that a dual outlet can only supply two loads totalling 10A and not 10A per outlet (which is how they are labelled).

timmmay

20858 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#2279115 18-Jul-2019 16:17

Please try to play nicely and get along with each other.

MadEngineer

4591 posts

Uber Geek
+1 received by user: 2570

Trusted

#2279150 18-Jul-2019 17:14

You need to check the manufacturers specifications, for example some simply say 10A which is for your interpretation. Others will for example specify 16A/total, 10A/socket. PDL695T is an example of that.

You're not on Atlantis anymore, Duncan Idaho.

MadEngineer

4591 posts

Uber Geek
+1 received by user: 2570

Trusted

#2279158 18-Jul-2019 17:44

And consider the PDL644 - a four-gang outlet with four 10A sockets that has the same rating as those above. I think that speaks for itself.

You're not on Atlantis anymore, Duncan Idaho.

Bung

6733 posts

Uber Geek
+1 received by user: 2926

Subscriber

#2279184 18-Jul-2019 18:01

AS/NZS3112 is the plug and socket standard. As already stated only 1 socket on the faceplate is tested at full current so there is no provision for a higher rating. In the past double sockets were 2 single sockets mounted on a common faceplate and strapped together at time of connection. My memory doesn't go back far enough for their rating.

RunningMan

9186 posts

Uber Geek
+1 received by user: 4840

#2279186 18-Jul-2019 18:02

What about a PDL 693/2? Two individual outlets on one faceplate.

Lego

Shop now for Lego sets and other gifts (affiliate link).

Jase2985

13732 posts

Uber Geek
+1 received by user: 6205

ID Verified

Lifetime subscriber

#2279218 18-Jul-2019 19:51

@irongarment thats not how it works.

go download the AS/NZS standard and do some reading instead of posting incorrect and potentially dangerous information.

gregmcc

2173 posts

Uber Geek
+1 received by user: 836

ID Verified

Trusted

Lifetime subscriber

#2279223 18-Jul-2019 20:02

RunningMan:

What about a PDL 693/2? Two individual outlets on one faceplate.

Easiest way is to go and search for the Sdoc, this will contain the answers

irongarment

280 posts

Ultimate Geek
+1 received by user: 134
Inactive user

#2279241 18-Jul-2019 20:20

Jase2985:
@irongarment thats not how it works.

go download the AS/NZS standard and do some reading instead of posting incorrect and potentially dangerous information.

Well I would, but the standards website is not playing nice for me right now. I can't download the guide for homeowners, and the full standard costs over $100.

I can't see how it's dangerous.

If I have a dual socket with 10A stamped on each one then I can draw 10A from either one. Inside the fitting let's call one socket A and the other B. Let's say the terminals connect directly to A and there is some internal connection AB to B. Let's say an appropriately sized cable is fed from an appropriately sized breaker. Let's start with fat cables and a 30A breaker.

So, I can draw 10A from A, and that's fine. 10A flows through the breaker and the wire through A and to the load. No current flows in link AB. Next I unplug from A and plug into B. 10A flows from the breaker through the wire to A then through link AB to B and to the load.

Now I plug two 10A loads in. One in A and one in B. 20A flows to A, 10A goes out the socket A, 10A goes through link AB and out of B. No part of the system exceeds its maximum.

Finally, you present a dual outlet to any member of the public. At what point do you tell them you can't plug two 2kW oil heaters into the sockets? Answer: never. Because that would mean a member of the public would need special training to plug stuff in. Since they don't have it it is not necessary, ergo it's not dangerous.

None of the dual outlets in my house are labelled 'total current must not exceed 10A'. Every socket is labelled 10A. How am supposed to know otherwise?

My cable is obviously a bit smaller, because my breaker is 16A. If I plugged two 10A loads in it would trip, but if I had thicker wire and a bigger breaker it wouldn't. And it would still be safe.

cyril7

9075 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#2279266 18-Jul-2019 20:30

Hi, you must remember that the rating of the MCB that feeds a single circuit has to take into account the overall length of that circuit, hence technically a 2.5mm TPS cable can be protected by a 20A MCB, but as the circuit lenth increases this must be derated, therefore its common to have 16A MCBs on house power outlet circuits.

So yes you are correct you can in theory connect two 10A loads to a dual outlet and assuming there is a 20A MCB supplying that circuit its all fine and dandy, however in reality cable lengths may crimp that back to 16A.

Just a point on tone of voice, I am sure you are level headed and not trying to be offensive, but the folk that have responded here are mostly professionals who do this work everyday, just like most of us early on in your work life you learn some basic rules and understandings and automatically apply them to everday work, these automated duties typically deliver trade related compliant outcomes, please offer some respect for those that have come here to offer the advise in their own time.

Cyril

irongarment

280 posts

Ultimate Geek
+1 received by user: 134
Inactive user

#2279281 18-Jul-2019 20:52

cyril7:
Hi, you must remember that the rating of the MCB that feeds a single circuit has to take into account the overall length of that circuit, hence technically a 2.5mm TPS cable can be protected by a 20A MCB, but as the circuit lenth increases this must be derated, therefore its common to have 16A MCBs on house power outlet circuits.

So yes you are correct you can in theory connect two 10A loads to a dual outlet and assuming there is a 20A MCB supplying that circuit its all fine and dandy, however in reality cable lengths may crimp that back to 16A.

Just a point on tone of voice, I am sure you are level headed and not trying to be offensive, but the folk that have responded here are mostly professionals who do this work everyday, just like most of us early on in your work life you learn some basic rules and understandings and automatically apply them to everday work, these automated duties typically deliver trade related compliant outcomes, please offer some respect for those that have come here to offer the advise in their own time.

Cyril

Thanks for that. It is a thoughtful reply. Most of the replies have been regurgitation of speculation and hearsay with no facts to back them up, or no evidence of any reasoning behind them. I thoroughly respect professionals who can state their opinion based on sound logic, or recite facts as facts.

I realise now that only one socket is tested, but I still fail to see why drawing 10A each from two outlets in the same box is any different to drawing 10A each from two single sockets sitting side by side. If this was the case people would be advised and the government would insist on an appropriately worded warning label in the outlet, just as they do for power boards and other electrical items.

Geekzone

Want to support Geekzone and browse the site without the ads? Subscribe to Geekzone now (monthly, annual and lifetime options).

gregmcc

2173 posts

Uber Geek
+1 received by user: 836

ID Verified

Trusted

Lifetime subscriber

#2279287 18-Jul-2019 21:06

irongarment:
cyril7:

Hi, you must remember that the rating of the MCB that feeds a single circuit has to take into account the overall length of that circuit, hence technically a 2.5mm TPS cable can be protected by a 20A MCB, but as the circuit lenth increases this must be derated, therefore its common to have 16A MCBs on house power outlet circuits.

So yes you are correct you can in theory connect two 10A loads to a dual outlet and assuming there is a 20A MCB supplying that circuit its all fine and dandy, however in reality cable lengths may crimp that back to 16A.

Just a point on tone of voice, I am sure you are level headed and not trying to be offensive, but the folk that have responded here are mostly professionals who do this work everyday, just like most of us early on in your work life you learn some basic rules and understandings and automatically apply them to everday work, these automated duties typically deliver trade related compliant outcomes, please offer some respect for those that have come here to offer the advise in their own time.

Cyril

Thanks for that. It is a thoughtful reply. Most of the replies have been regurgitation of speculation and hearsay with no facts to back them up, or no evidence of any reasoning behind them. I thoroughly respect professionals who can state their opinion based on sound logic, or recite facts as facts.

I realise now that only one socket is tested, but I still fail to see why drawing 10A each from two outlets in the same box is any different to drawing 10A each from two single sockets sitting side by side. If this was the case people would be advised and the government would insist on an appropriately worded warning label in the outlet, just as they do for power boards and other electrical items.

More than likely the way the screw terminal is bonded to the internal links to pins on the outlet is the reason why "up to 16A" is stated.

cyril7

9075 posts

Uber Geek
+1 received by user: 2499

ID Verified

Trusted

Subscriber

#2279289 18-Jul-2019 21:09

yep the common conductor components are the key detail here.

Cyril

MadEngineer

4591 posts

Uber Geek
+1 received by user: 2570

Trusted

#2279318 18-Jul-2019 22:37

RunningMan:
What about a PDL 693/2? Two individual outlets on one faceplate.

this is also rated at only 10A. Even though you could run two individual cables to it — which it’s designed for eg where you could have each cable then remotely individually switched. The issue would be if you were daft enough to daisy chain one outlet to the other where the termination at the back of the common would then have to carry the load of both. Instead of wiring it like that you’d just buy a 695.

You're not on Atlantis anymore, Duncan Idaho.

Bung

6733 posts

Uber Geek
+1 received by user: 2926

Subscriber

#2279330 18-Jul-2019 23:06

MadEngineer: . The issue would be if you were daft enough to daisy chain one outlet to the other where the termination at the back of the common would then have to carry the load of both. Instead of wiring it like that you’d just buy a 695.

Why would daisy chaining be any different terminal wise than the common series connection to another socket?2.5mm wire would have more cross section than some internal strapping. It seems to come down to the Standard having no provision for rating multi 10A socket fittings higher than 10A. There would have to be a test loading all sockets.

There are cover plates that clip over 2 fittings on a double box.

1 | 2 | 3