Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 | 3
930 posts

Ultimate Geek


  # 1006740 16-Mar-2014 15:19
Send private message

Bung:
gregmcc:
Bung: The only thing typically 10A is the cheap breaker built into plug strips. The fuse or breaker rating is determined by the .cable and its surroundings. Short term current higher than nominal probably wouldn't trip either. In an office if you ever manage to trip the breaker it's surprising sometimes how many other computers are affected.



I think you need to re-read what you said here, the fuse or breaker rating IS NOT determined by the cable and it's surrroundings, you need to go and take a look at a circuit breaker and read the number on it, a 10A circuit breaker has a rating of 10 amps.


Step back a bit. How does the rating of the protection get chosen? Do you see 1 socket and put in a 10 amp breaker or do you look at the appropriate breaker for the size of cable and how surrounded in insulation it will be?

]


Strictly speaking the circuit breaker is chosen to protect the cable, so a 2.5mm cable could have a 20-25A breaker on it even though the socket outlets are rated for 10A.

You should never try and draw more than 10A from a 10A rated plug/socket, doing this over an extended period can cause overheating and a fire.

22344 posts

Uber Geek

Trusted
Subscriber

  # 1006870 16-Mar-2014 20:52
Send private message

2.5mm should be 16A if the cable is surrounded by insulation, 20 if it is in free air. Then there is the earth loop impedance which may require derating the cable - same thing that causes derating due to length.

Not uncommon for large houses to have to have 4mm power circuits just to get a 20 amp breaker on it, havent seen anyone have to go to 6mm ever.

Old houses are likly to have a 1.5mm or whatever the inch equivilant was, so that should be on a 10A if it is surrounded by insulation or 15/16 if not.

More to the point is the condition of the wall socket - old ones stretch and get hot from poor connections.




Richard rich.ms

 
 
 
 


930 posts

Ultimate Geek


  # 1006943 16-Mar-2014 22:01
Send private message

richms: 2.5mm should be 16A if the cable is surrounded by insulation, 20 if it is in free air. Then there is the earth loop impedance which may require derating the cable - same thing that causes derating due to length.

Not uncommon for large houses to have to have 4mm power circuits just to get a 20 amp breaker on it, havent seen anyone have to go to 6mm ever.

Old houses are likly to have a 1.5mm or whatever the inch equivilant was, so that should be on a 10A if it is surrounded by insulation or 15/16 if not.

More to the point is the condition of the wall socket - old ones stretch and get hot from poor connections.




Old imperial size was called "Three-oh-two-nine", three strands of 0.029inch

468 posts

Ultimate Geek


  # 1010913 22-Mar-2014 00:18
Send private message

as a sparky i can tell you now that 90% of power circuits are fed by a 20A breaker. each breaker usually has 5-6 outlets on it.
in the scheme of things the 10A socket outlet is the weakest link in the chain. you could theoretically pull 20A through one socket outlet and the breaker wont trip...but your wall may catch on fire.

two PC's arent going to pull huge amps unless both are 750W monsters running at 100% capacity which i doubt.

you could always get a sparky around to change your single outlet for a double (or even quad) outlet.

2901 posts

Uber Geek


  # 1010922 22-Mar-2014 05:05
Send private message

floydie: you could always get a sparky around to change your single outlet for a double (or even quad) outlet.


Check the rating of the fitting, it will probably still be 10A total rather than per outlet. ]

468 posts

Ultimate Geek


  # 1011113 22-Mar-2014 19:23
Send private message

no. sockets outlets are rated at 10A per socket. thats the law.
so a normal double PP has 2X10A outlets on one faceplate.

22344 posts

Uber Geek

Trusted
Subscriber

  # 1011115 22-Mar-2014 19:26
Send private message

I'd love to see what 40A would do to one of the quad outlets then ;)




Richard rich.ms

 
 
 
 


gzt

10862 posts

Uber Geek


  # 1011181 22-Mar-2014 22:31
Send private message

Bung's not making much sense there.

The Brits solve this problem with fused plugs.

I do wonder about this situation. It does seem like random hopes in some way. NZ mandated RCD's long back which is better than nothing, but again it's a luck thing that might get an earth fault in the scenario.




Signature goes here.

2901 posts

Uber Geek


  # 1011190 22-Mar-2014 23:17
Send private message

gzt: Bung's not making much sense there.

The Brits solve this problem with fused plugs.

I do wonder about this situation. It does seem like random hopes in some way. NZ mandated RCD's long back which is better than nothing, but again it's a luck thing that might get an earth fault in the scenario.



I'm just repeating what Energy Safety feed the public.

Electrical Code of Practice for
Homeowner/Occupier’s Electrical Wiring Work in Domestic
Installations 2004 (NZECP 51:2004)

"B2 SOCKET-OUTLETS
B2.1 Never overload socket-outlets. Socket-outlets are designed
to take one or two electrical appliances, (the total current
rating of a double socket-outlet is 10 A). "

I've seen AS/NZS 3112 quoted as the source of this rating but I can't find it online. I know that the temperature rise test only uses 1 outlet. If the fitting has a rating that is the sum of the socket ratings you'd expect all sockets to be loaded during testing.



gzt

10862 posts

Uber Geek


  # 1011200 22-Mar-2014 23:56
Send private message

Thanks for that, I completely missed the point first time round. Cheers. ; )




Signature goes here.

1990 posts

Uber Geek

Trusted

  # 1011433 23-Mar-2014 17:02
Send private message

Lizard1977: Thanks. I figured the socket would be 10A, but I wasn't sure whether that 10A would be shared across all the sockets in the room. Our fuse board is on the old-ish side (that's a whole other story) and it looks like the fuse/circuit breaker is either 16A or 6A (i'm guessing the former).

The PCs wouldn't be at full load all the time, but I figured the PSU wattage would indicate maximum usage. I reckon the total maximum wattage would be no higher than 1700W, which at 240V gives about 7A and 34ohms. So I think the single socket approach should be fine...

In full use by a user is different from full capacity power draw, so you are still unlikely to ever use more than half of maximum except possibly during startup if you have 4 hard drives in each PC etc etc.

The usual problem is that the PC and router etc are on the same circuit that you later want to plug a heater or vacuum into, which do use all their power rating (close to the 10A circuit capacity) when running at full speed. If it doesnt trip the breaker you could still be running the circuit at close to capacity a bit too frequently.




Qualified in business, certified in fibre, stuck in copper, have to keep going  ^_^

468 posts

Ultimate Geek


  # 1011471 23-Mar-2014 19:38
Send private message

the regs count a double outlet the same as a single for the purposes of calculating maximum demand and the number of outlets on a RCBO. that doesnt mean that the physical outlet is only capable of  carrying 10A. as i said...each socket can carry 10Amps. if the "shared 10A theory" was true, your house would burn down every time you plugged a portable heater in to one of the sockets a double outlet.

I certainly would not consider any fitting that couldnt internally handle the 20A combined of both sockets to be electrically safe.

( i think from memory the quad outlets are counted as a 16A total rated for MD calculations but would have to check on that..)

2901 posts

Uber Geek


  # 1011498 23-Mar-2014 20:55
Send private message

A test would be two heaters. The duty cycle on most other combinations wouldn't do much. If you recall the old PDL double. That was two singles on one faceplate that had to be strapped together. The modern double has the contacts arranged more like cheap plug strips.

gzt

10862 posts

Uber Geek


  # 1011516 23-Mar-2014 22:03
Send private message

That is a not a great idea. Edit: Due to potential risk it is a bit silly in a domestic context.

BTR

1514 posts

Uber Geek


  # 1011595 24-Mar-2014 09:20
Send private message

sbiddle: A standard power socket is rated at 10A and the fuse or circuit breaker will typically be 10A, but could be 15A. Basic ohms law will let you work out the load.



You might actually find that in most domestic cases that the MCB (circuit breaker) is actually 20 amp for power sockets, 10 amp for lights and usually 16amp for hot water cylinder.

If OP is worried why not upgrade the single socket to a dual and get a sparky to install a second dual next to the existing socket. Would cost less than $150 to do this.

1 | 2 | 3
Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Intel expands 10th Gen Intel Core Mobile processor family
Posted 23-Aug-2019 10:22


Digital innovation drives new investment provider
Posted 23-Aug-2019 08:29


Catalyst Cloud becomes a Kubernetes Certified Service Provider (KCSP)
Posted 23-Aug-2019 08:21


New AI legaltech product launched in New Zealand
Posted 21-Aug-2019 17:01


Yubico launches first Lightning-compatible security key, the YubiKey 5Ci
Posted 21-Aug-2019 16:46


Disney+ streaming service confirmed launch in New Zealand
Posted 20-Aug-2019 09:29


Industry plan could create a billion dollar interactive games sector
Posted 19-Aug-2019 20:41


Personal cyber insurance a New Zealand first
Posted 19-Aug-2019 20:26


University of Waikato launches space for esports
Posted 19-Aug-2019 20:20


D-Link ANZ expands mydlink ecosystem with new mydlink Mini Wi-Fi Smart Plug
Posted 19-Aug-2019 20:14


Kiwi workers still falling victim to old cyber tricks
Posted 12-Aug-2019 20:47


Lightning Lab GovTech launches 2019 programme
Posted 12-Aug-2019 20:41


Epson launches portable laser projector
Posted 12-Aug-2019 20:27


Huawei launches new distributed HarmonyOS
Posted 12-Aug-2019 20:20


Lenovo introduces single-socket servers for edge and data-intensive workloads
Posted 9-Aug-2019 21:26



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.