How many appliances per socket?

robocode

My girlfriend just bought a fish tank which has three separate things needing power (the temp regulator, the lighting, and the filter). I only have two sockets near this and they are taken up by the tv and sky box. Is it fine to just connect an adapter to one of the sockets and then plug the tv, and 3 fish tank things into that adapter?

Bruthal

robocode wrote: »

My girlfriend just bought a fish tank which has three separate things needing power (the temp regulator, the lighting, and the filter). I only have two sockets near this and they are taken up by the tv and sky box. Is it fine to just connect an adapter to one of the sockets and then plug the tv, and 3 fish tank things into that adapter?

It should be ok. Id recommend one of those short extension leads with 4 sockets on them rather than one of them plug in multi adaptor things.

coylemj

Bruthal wrote: »

It should be ok. Id recommend one of those short extension leads with 4 sockets on them rather than one of them plug in multi adaptor things.

+1 The TV will consume much more juice than the Sky box so leave that on a socket by itself and plug the Sky box plus the fish tank gear into a socket board.

robocode

Great stuff, thanks!

SpaceTime

Overloading an Irish socket's actually relatively hard to do because of the fused plugs. The major risk is if you're using an unfused double adaptor (a completely stupid device that should be banned in my opinion).

A socket will handle up to 13amps safely. So, at 230V that's 13*230 = 2990 Watts. That's why you'll never see an appliance in the UK and Ireland rated at more than 3kW (most being about 2900W max).

(Some continental appliances can go higher as they've 16amp sockets but it's usually just tumble dryers and a few items like that that ever use the full 16A)

You would need to get the maximum rated wattage of each appliance and add them all up.

If you're using a power-strip socket, make sure that it's suitable to carry the load too. Some of them are only rated 10amps in which case your limit is about 2300W.

Also if there are any extension leads involved, beware of the limits written on them. Sometimes they can be limited to much less than 13A, especially if they're reels.


....


I would not recommend that you ever use those plug-in 4-way sockets that they seem to be selling in a few places. They put too much physical strain on the sockets and can pull them out of the wall / damage terminals and I'm not sure if they're fused.

Also, avoid traditional double-adaptors as they're rarely fused and you can easily overload a socket with them by plugging in two heavy appliances. I've seen them cause fires in kitchens where someone plugs two heavy appliances into a single socket using them and because there's no fuse in the adaptor itself, it will allow a full 26A to flow i.e. both 13A plugs.

The best solution is a short cable to a 4-way socket and a fused plug on the end that's going into the wall.

...

Also, if the fuse blows in the extension lead plug, do not replace it with a higher rating than was originally installed. That's a recipe for a fire.

danjo-xx

Surprised these type of adaptors are legal as they must be prone to failure due to pressure on the main pins due to stress n strain. Maybe not a safety risk but still!

Andrew_Doran

Are those on sale here? Cheap and nasty seems the norm nowadays with most all white goods. The brother and I were reminiscing about these recently (hopefully image displays):

SpaceTime

You could buy those in B&Q until quite recently (proper MK plugs).

You can still get them in a few places. They're nearly too well made though given the huge size of them

You can certainly buy MK plugs online if you want them. They're quite widely available as the company still makes probably some of the best sockets and fittings on the market. Their fittings are still pretty top notch.

We installed them in the house because there are small kids around and their sockets are far more kid-proof than the standard ones. You have to insert the earth pin and also put equal pressure on the outer edges of the live and neutral 'holes' before they'll open. Where as you can just open the normal type with a screwdriver or a pencil in the earth 'hole'. They are *extremely* kid-proof.

It's next to impossible to defeat the shutter system without a lot of ingenuity and several tools simultaneously.

The only thing I would say is that those old huge plugs (including some that are currently on the market) is that they are made from urea formaldehyde (basically bakelite) which makes them very heavy and bulky. It's the same material they make sockets and switches from.

Modern plastics are capable of providing a better result in many ways as they're heat-resisant enough to cope with a hot fuse / melting wire, they're fire-resistant, they're much lighter and from a safety point of view, they're much less prone to cracking. They're probably a lot more suitable for use in plugs which can get a fair bit of abuse and knocking around.

One of the problems with that type of plug is that if it falls / gets a serious bang it can crack open exposing some of the electrical components. It used to be a huge problem until the 1990s as most plugs were made from that brittle bakelite stuff and it was pretty common to find broken plugs in use.

With modern versions, it's pretty rare to find a broken / shattered plug.

Old and bulky doesn't always mean better

SpaceTime

danjo-xx wrote: »

Surprised these type of adaptors are legal as they must be prone to failure due to pressure on the main pins due to stress n strain. Maybe not a safety risk but still!

Plug in a few of those heavy transformer plugs and you could probably take down the wall, never mind the pins!

Tow

I have used Duraplugs for a few years now, I think they are now owned by MK.

What ever you do, don't buy the 'Electrolite' plugs they sell in the 2 Euro shops. I bought a pack of two a few weeks ago and the cover 'fell' off one as soon as I opened the packet. The plastic column the screw goes into had snapped of the top of the plug. I brought it back into the shop, but they had no interest, just wanted me to bring in the second plug so they could change it!! I keep meaning to send the plug into the National Consumer Agency for testing.

Anyway, this is a Duraplug and is well worth being for times the price of a Euro shop plug:

SpaceTime

Yeah, seems they are part of MK http://www.mkelectric.com/en-gb/Products/WD/PortablePower/duraplug/Pages/default.aspx

Andrew_Doran

SpaceTime wrote: »

You can certainly buy MK plugs online if you want them. They're quite widely available as the company still makes probably some of the best sockets and fittings on the market. Their fittings are still pretty top notch.

We installed them in the house because there are small kids around and their sockets are far more kid-proof than the standard ones. You have to insert the earth pin and also put equal pressure on the outer edges of the live and neutral 'holes' before they'll open. Where as you can just open the normal type with a screwdriver or a pencil in the earth 'hole'. They are *extremely* kid-proof.

It's next to impossible to defeat the shutter system without a lot of ingenuity and several tools simultaneously.

I have done the same in my own home. All sockets replaced with MK Logic Plus. The quality of some that were in my house when we bought it were shocking (pardon the pun), including two sockets that accepted two pin euro plugs, no earth pin required to open the shutters.

Bruthal

Andrew_Doran wrote: »

I have done the same in my own home. All sockets replaced with MK Logic Plus. The quality of some that were in my house when we bought it were shocking (pardon the pun), including two sockets that accepted two pin euro plugs, no earth pin required to open the shutters.

Some sockets are designed to open when both L and N pins go in together.

SpaceTime

They should only open though when the pressure is out on the outer edges of the two shutters. If you notice for example, MK sockets of the older type worked that way but they will specifically not open for Europlugs.

The big issue with Europlugs is that if someone were to plug them into a ring circuit (32A) the wouldn't be adequate protection for the cable.
When they're used on the continent they only have 16Amp (or sometimes 20Amp) radials which are considered to be adequate protection for the appliance cable.
Ring's are very much a UK-only thing which Ireland also uses (but much less frequently) but that's what necessitates the fuse in the plug.

Properly implemented, modern versions of the continental systems are extremely safe and have the big advantage of not always needing enormous plugs for small appliances.

The fused plugs are a slight advantage, but I haven't really seen any issues with continental systems being any more fire prone than ours are. They're both pretty safe.

The UK / Ireland system never seems to have foreseen the need to have lots of small, portable appliances. Every plug seems to have been designed with a 3kW electric kettle in mind.

Andrew_Doran

Bruthal wrote: »

Some sockets are designed to open when both L and N pins go in together.

Understood. A single screwdriver was enough to open the shutters on one of the units I had (applied to L/N). I didn't bother playing with the other one. Maybe the mechanism was broken. In any case not tolerable with inquisitive young children about.

paddy147

danjo-xx wrote: »

Surprised these type of adaptors are legal as they must be prone to failure due to pressure on the main pins due to stress n strain. Maybe not a safety risk but still!

They are regulary on sale in Lidl and Aldi for around 6 euro.

SpaceTime

They look like something waiting to be banned

Sockets can only hold so much!

Bruthal

SpaceTime wrote: »

The big issue with Europlugs is that if someone were to plug them into a ring circuit (32A) the wouldn't be adequate protection for the cable.

It would be interesting to come up with a circumstance in which a small appliance would create a sustained overload on its cable. Its not very likely.

tomdempsey200

ya

toasters and the like are wired in 0.75 and fused at 13amp

one of the problems with the 13amp plug is the fuse overheating and causing damage on sustained loads

Bruthal

Yea there is that problem alright.

SpaceTime

Bruthal wrote: »

It would be interesting to come up with a circumstance in which a small appliance would create a sustained overload on its cable. Its not very likely.

I suppose it could happen if you had a direct short between live and neutral. Not likely, but that's pretty much the theory behind the fuses in the plugs here.

On the continent and in the states, they just assume that any appliance or cord should be capable of surviving a 15 or 16Amp fault.

The plug fuses also react very slowly anyway. Where I have had a situation where there's a straight short circuit, I have noticed that the MCB trips (at 20amps) long before the fuse blows.

Bruthal

SpaceTime wrote: »

I suppose it could happen if you had a direct short between live and neutral. Not likely, but that's pretty much the theory behind the fuses in the plugs here.

It wont likely create a sustained overload though. It either trips the MCB, or instantly blows the short clear.

The plug fuses also react very slowly anyway. Where I have had a situation where there's a straight short circuit, I have noticed that the MCB trips (at 20amps) long before the fuse blows.

It could be looked at that the MCB is extremely fast, rather than the fuse being very slow possibly.

The starting current of a motor or transformer for example, can trip MCBs, while fuses in plugs are fine, due to the extremely short duration of such currents.

SpaceTime

They are probably designed to some 1940s / 1950s standard though too. They were designed to be used in conjunction with 30 amp British style rewirable fuses. Some of those were very slow reacting and very primitive .

Modern MCBs and even DZ fuses are fairly fast to trip /blow.