Overloading a single NZ wall power socket? Daisy-chaining x2 power boards?

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#2261997 21-Jun-2019 15:12

I would also encourage you to check that all of the fuses in your cabinet have the correct fuse wire installed if you haven't already done so since you moved in. A previous tenant at my place was brainless enough to replace fuse wire with a paperclip in one of mine.

TheMantis

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#2262045 21-Jun-2019 15:47

Technofreak:
sen8or: Standard 10 amp socket should be good for around 4kw of power drain before tripping the circuit breaker / fuse (I think its 4.4 but could be mistaken).

I think you are mistaken. As far as I know 2400 watts (2.4kw) is the maximum you should draw from a 10 amp socket. See my post above.

You're both mistaken: Standard low voltage is 230V. Sockets are rated at 10A typically, therefore 2.3kW but only for a purely resistive load. A double socket outlet will provide twice this assuming the circuit is correctly protected with a 20A MCB.

Never, ever daisy chain extension cords, multiboxes, or double adapters (these shouldn't be used at all, full stop). Also, the overload protection on multiboxes are notoriously rubbish - don't rely on them for any sort of protection at all.

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#2262068 21-Jun-2019 16:16

TheMantis:
You're both mistaken: Standard low voltage is 230V. Sockets are rated at 10A typically, therefore 2.3kW but only for a purely resistive load. A double socket outlet will provide twice this assuming the circuit is correctly protected with a 20A MCB.

Never, ever daisy chain extension cords, multiboxes, or double adapters (these shouldn't be used at all, full stop). Also, the overload protection on multiboxes are notoriously rubbish - don't rely on them for any sort of protection at all.

I think you'll find the AC voltage in New Zealand is 230/240.

I'm not sure but I think the legal minimum voltage that is supposed to be supplied by your supplier is 230 and the maximum is 240. As the load on the network varies during the day the voltage will fluctuate.

So 2.4 is is entirely possible. In fact many portable electric heaters are 2.4kw heaters.

I think your statement to never daisy chain extension cords or multi boxes is over the top. I would agree that prudence needs to be exercised and daisy chaining to power high draw items has some risk, but for low drain items like computer equipment, led lights etc the risk is extremely low.

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TheMantis

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#2262072 21-Jun-2019 16:46

Technofreak:
TheMantis:
You're both mistaken: Standard low voltage is 230V. Sockets are rated at 10A typically, therefore 2.3kW but only for a purely resistive load. A double socket outlet will provide twice this assuming the circuit is correctly protected with a 20A MCB.

Never, ever daisy chain extension cords, multiboxes, or double adapters (these shouldn't be used at all, full stop). Also, the overload protection on multiboxes are notoriously rubbish - don't rely on them for any sort of protection at all.

I think you'll find the AC voltage in New Zealand is 230/240.

I'm not sure but I think the legal minimum voltage that is supposed to be supplied by your supplier is 230 and the maximum is 240. As the load on the network varies during the day the voltage will fluctuate.

So 2.4 is is entirely possible. In fact many portable electric heaters are 2.4kw heaters.

I think your statement to never daisy chain extension cords or multi boxes is over the top. I would agree that prudence needs to be exercised and daisy chaining to power high draw items has some risk, but for low drain items like computer equipment, led lights etc the risk is extremely low.

E(S)R 4

standard low voltage means,—

(a) in respect of electricity supplied by either a single-phase MEN system or a multiple-phase MEN system, a nominal voltage of 230 volts AC between phase and neutral

E(S)R 28:

(1) The supply of electricity to installations operating at a voltage of 200 volts AC or more but not exceeding 250 volts AC (calculated or measured at the point of supply)—

(a) must be at standard low voltage; and

(b) except for momentary fluctuations, must be kept within 6% of that voltage.

Low risk doesn't equal no risk. It is bad practice to daisy chain an extension lead, epod, or similar that has not been specifically designed for that purpose.

gregmcc

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#2262075 21-Jun-2019 17:00

Standard low voltage (typical power point) in NZ is 230V. +/-6% (216.2-243.8v)

As far as how much power you can draw from a standard wall socket depends on what kind of protection is at your fuse board, a 10A circuit breaker or fuse will not trip at 10 amps, it's time vs. load dependent, the higher the load the shorter the time until it trips.

If your in a house with older wiring there is a very real risk of causing a fire when wall sockets are overloaded, the pins on the sockets may have lost their spring tension causing a higher than normal resistance which could result in a "hot spot", if there are old re-wireable fuses who know what size fuse wire is in there, and 2 x 5A fuse wires is not the same as 1 x 10A fuse wire.

Basically if your in a older house with old wiring then you need to be a bit sensible on what you actually plug in.

neb

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#2262077 21-Jun-2019 17:06

1101:
Are HPM still a quality brand ?

Well, they used to be. I pulled apart an HPM power board that failed and it was... well, not as bad as the cheap Chinese junk you'll get at the Warehouse, but not far above it either. I've got 20-year-old HPM power boards that are built like tanks compared to what they're currently selling.

It's the race to the bottom, they have to compete with the cheapest possible junk so they've had to cut corners wherever they can too.

SirHumphreyAppleby

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#2262115 21-Jun-2019 18:15

neb: It's the race to the bottom, they have to compete with the cheapest possible junk so they've had to cut corners wherever they can too.

It's a regulated product. There is no excuse for the quality to be as poor as it is. Products which don't meet the standards need to be pulled from the shelves and importers fined.

We've seen plenty of questionable updates to the standards, often putting safety for the sake of it ahead of relying on simple common sense, so why can't they enforce quality standards for multi-boards? The big chains are all selling these, it's not like these poor quality items are being parallel imported and sold just in $2 stores.

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nickb800

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#2262127 21-Jun-2019 18:39

If you are going to daisy chain multiboards, then they don't all need to be surge protecting - the first one will be sufficient.

Another approach to safety, provided that other sockets on the same circuit don't serve high loads, is to change the fuse /circuit breaker down to 10 amp. That way the circuit is limited to a safe level for the socket, and you are less reliant on cheap circuit breakers in the multi boards for safety. Personally I'd just daisy chain the multi boards and be careful, but everyone has different approaches to risk

richms

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#2262128 21-Jun-2019 18:41

neb:
1101:

Are HPM still a quality brand ?

Well, they used to be. I pulled apart an HPM power board that failed and it was... well, not as bad as the cheap Chinese junk you'll get at the Warehouse, but not far above it either. I've got 20-year-old HPM power boards that are built like tanks compared to what they're currently selling. It's the race to the bottom, they have to compete with the cheapest possible junk so they've had to cut corners wherever they can too.

I have many cheap 6 ways that are now 3 ways because I have had to put a big X in sharpie over some of them that will not hold a plug anymore. Plug something in at the wrong angle and crunch, somethings bent and it will never hold a plug again. All the HPM 8 ways and 5 way spaced out ones are ok so far but they dont hold as well as the old ones did.

Richard rich.ms

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#2262132 21-Jun-2019 18:51

I have an 1918-vintage villa with antique single power points.

Instead of using nasty powerboards, I self-installed quad switch socket outlets throughout the house ...

horizontal:

vertical:

These are of good quality, they are widely available, and are designed for Australian/NZ conditions and voltages.

I have five of them in my geeky computer room (= 20 power points). No powerboards at all.

[5-switch versions are also available]

Sideface

neb

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#2262133 21-Jun-2019 18:53

Worst one I've experienced, and not sure if it was HPM but it certainly wasn't a Warehouse special, wasn't a crunch but a bang, followed by the plug prongs being blackened, probably a variation of what @richms reported above. Tossed the whole power board.

neb

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#2262135 21-Jun-2019 18:56

Sideface:
Instead of using nasty powerboards, I self-installed quad switch socket outlets throughout the house ...

Yep, those came up recently in another thread, I've put those in most rooms except one outlet where I can't figure out which MCB disconnects it, and I don't want to pull power to the whole house just to change it. See "Casa de Cowboy" mentions in other threads...

Edited to add: To put this into perspective, the MCB for master bedroom in the north end of the house also controls the outdoors light on the south end of the house. The labelling of MCBs on the power board isn't so much a set of labels as a kind of fully connected graph.

richms

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#2262137 21-Jun-2019 19:00

neb:
Sideface:

Instead of using nasty powerboards, I self-installed quad switch socket outlets throughout the house ...

Yep, those came up recently in another thread, I've put those in most rooms except one outlet where I can't figure out which MCB disconnects it, and I don't want to pull power to the whole house just to change it. See "Casa de Cowboy" mentions in other threads... Edited to add: To put this into perspective, the MCB for master bedroom in the north end of the house also controls the outdoors light on the south end of the house. The labelling of MCBs on the power board isn't so much a set of labels as a kind of fully connected graph.

Perhaps it is a special pre-meter power outlet. A friend found one of those in their flat once.

Richard rich.ms

Aredwood

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#2262182 21-Jun-2019 19:29

neb:
Sideface:
Instead of using nasty powerboards, I self-installed quad switch socket outlets throughout the house ...

Yep, those came up recently in another thread, I've put those in most rooms except one outlet where I can't figure out which MCB disconnects it, and I don't want to pull power to the whole house just to change it. See "Casa de Cowboy" mentions in other threads...

Edited to add: To put this into perspective, the MCB for master bedroom in the north end of the house also controls the outdoors light on the south end of the house. The labelling of MCBs on the power board isn't so much a set of labels as a kind of fully connected graph.

That mystery socket might be fed from a lighting circuit. Especially likely for bathroom sockets, due to people swapping out those shaver only sockets.

Could also be the load side of 2 different MCBs linked together. Meaning that you wont be able to trace which MCB feeds that socket, solely by turning off the MCBs 1 at a time.

It might also be fed from the hot water cylinder circuit, or an old nightstore heater circuit. Especially if those loads are supplied by a separate meter that is billed at a cheaper rate.

Kickinbac

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#2262196 21-Jun-2019 20:00

My advice is to install the double or quad power point as previously suggested. But sounds like you should get an electrician to inspect and install it.
But if not doing that at least use a plug in RCD and put a new smoke alarm in the room.

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