110v multiple sockets hard wired ?

[mattysupra]

Hi,

I would like to have installed 110v sockets. Require minimum 11 of them but ideal would be 21 of them depending on cost etc to my next question. I dont want to be using one of the yellow box transformers in each location so would like 110v sockets on the wall.

Is there some sort of large transformer / distribution board etc that can be installed and then 110v sockets running off it like a normal 240v ring ?

thanks in advance.

 

[ban-all-sheds]

Require minimum 11 of them but ideal would be 21 of them depending on cost etc

The cost of 10 sockets will probably be small in comparison to the cost of the transformer.

Is there some sort of large transformer

Yes.

Do you know what capacity and duty cycle you need?

distribution board etc that can be installed and then 110v sockets running off it like a normal 240v ring ?

You would not have these sockets on a ring.

 

[OwainDIYer]

Yes, but it is likely to be large and expensive.

Is this for a workplace where the Electricity At Work Regulations apply - and possibly requirements for emergency switching of machinery?

 

[ericmark]

The old BS 196 sockets with key ways can be used in the same way a 13A ring final but the standard yellow plugs don't have fuses in the plug so can't wire them as a ring. The BS 196 the pins were fuses.

So yes you can get a large transformer to run many sockets and to reduce the number of MCB's using three phase so a triple 16A MCB powers three 16A sockets rather than using a double pole MCB for every socket.

Many also use a 20A MCB to power 2 sockets but clearly that is open to overload.

Having 21 sockets could draw nearly 37 kW but clearly not all will be used together so you need to decide based on likely use what size will be required. So for example with 10 kVA having just 4 x triple pole 16A MCB's could be considered enough. With of course an input MCB as well. So 24 sockets with an average of 5A each but maximum still 16A.

This is where the planning comes in with 110 volt drop is a real problem. Caravan sites use posts with 4 sockets grouped together with there own MCB's these could be adapted for 110 volt use so a ring could be used to supply each group of three or four sockets.

Much depends on distances involved as to which system will work best. Do be careful selecting transformer as 110 is also used with neutral mainly for controlling large machines not all 110 transformers are centre tapped. For certain applications in the UK centre tap is required but even where it's not required if the transformer is not centre tapped than it has exactly same rules as 230 volt so you lose many of the advantages of using 110 volt.

 

[mattysupra]

Its a flooring training centre. So the sockets will be mounted in the students training bays.

Problem i have is a lot of the specialist tools are 110v as normally used on building sites. We at the training centre can use 240v but that dont help me with 110v tools.

The problem i have at the moment in the 110v transformers keep getting left switched on, as the tool is not on you dont realize the transformer is still on using power etc. Not sure if having a main distribution board or what ever we end up with will help this issue apart from one main kill switch maybe?

But more a issue is the transformers being in the way and if you move the transformers we end up running extension leads across the area which is a trip hazard and get damaged. So if the plugs are in the bays and the flex to the tools has the correct length on it (like the 240v tools) we eliminate the trip hazards and transformers being balanced on dwarf walls by students or extension leads being damaged.

The sort of tools being used are lister welders like so - http://tradeunderlay.com/products-p...ng-tools/leister-welder-110v-triac-s-hot-air/

We also have heavy equipment like the grinders - http://www.htc-floorsystems.com/en/Products/HTCGreyline/HTCGreyline270.aspx

 

[Adam_151]

Also bear in mind that at 55v to earth, max permitted Zs values are a quarter of what they are at 230v. Some of the loads you might want to use might require C types. If you are not careful, circuits which arn't really all that long require a cable CSA which is difficult to terminate in the sockets!

Now the disconnection time allowed to be longer than 5s (as the touch voltage is always below 50v), however you have got to watch that the energy driven into a fault until the breaker trips is below that which damages the conductor. Now also bear in mind that the adiabatic is not intended for disconnection times outside the range of 0.1-5s (however in excess of 5s it should produce a value that is on the safe side)

 

[mattysupra]

O.k ! the answers are getting a little over my head here LOL.

So the verdict is that yes we can have some sort of system fitted, but i get the idea its going to be expensive and possible specialist ? (in other words if i purchased what ever was recommended would a normal sparky be o.k installing ? )

The other idea which i have to keep things simple in my eyes unless you disagree (and might work out more expensive?)

Is to buy something like this or should i say a few of these -

http://www.ebay.co.uk/itm/10-KVA-Si...al_Components_Supplies_ET&hash=item2c6e54782e

And then run the flex to the sockets?

 

[mattysupra]

O.k ! the answers are getting a little over my head here LOL.

So the verdict is that yes we can have some sort of system fitted, but i get the idea its going to be expensive and possible specialist ? (in other words if i purchased what ever was recommended would a normal sparky be o.k installing ? )

The other idea which i have to keep things simple in my eyes unless you disagree (and might work out more expensive?)

Is to buy something like this or should i say a few of these -

http://www.ebay.co.uk/itm/10-KVA-Si...al_Components_Supplies_ET&hash=item2c6e54782e

And then run the flex to the sockets?

 

[333rocky333]

never done 110 socket supplys before but,

A certain chain store we work in use standard double pole mcbs in a 36 way board to feed 110 volt lighting circuits,
I sometimes wonder wether the mcbs are suitable.
The old school way used to be to use double pole hrc fuseboards

i know a certain builders chain uses a site transformer internal to feed standard yellow sockets outside, however the outside unit incorparates an RCD and that RCD is a special rated at 110 volt

 

[Adam_151]

i know a certain builders chain uses a site transformer internal to feed standard yellow sockets outside, however the outside unit incorparates an RCD and that RCD is a special rated at 110 volt

If the 110v system is correctly designed there is no need for an RCD. It would seem odd that someone would specify one

 

[ericmark]

I avoided the RCD question as it is unclear to if really required the regs I have even say RCD for SELV there are no exceptions which is clearly daft. So with 55 - 0 - 55 it is down to the designer.

The 10 kVA transformer you selected would likely do what is required. Even at 17.58 amp likely it would run from a 16 amp supply but it is common to run two 16 amp sockets from one 20 amp MCB.

However as a training establishment even if you can get away with a 16 amp plug the question is should you? Or as part of the training should students be aware they need a 32 amp supply?

In the days before the Laing buy out they had all their transformers with twin 16 amp sockets to each 20 amp MCB. But in Sizewell power station the transformers were supplied by Nuclear Electric who were sticklers for the rules so every 16 amp socket had it's own 16 amp MCB. This caused no end of problems as vacuum cleaners and large angle grinders exceeded 16 amp and were tripping the 16 amp MCB's in the supply transformers. It was a regular job to swap a 16 amp plug for a 32 amp plug or a three phase 16 amp.

One would hope any electrician could install the transformer and supply network but again in Sizewell I found the charge hand electrician had wired the garage with a 32 amp ring powering 16 amp sockets but he was an ex-house basher an am sure any industrial electrician would know what he is doing.

The advantage of the transformer you link to is it uses far less current when on stand by than the yellow bricks so even if left on 24/7 it's not really a problem. It also lends its self to using emergency stop buttons which may be a consideration in a training workshop.

The yellow bricks often break the rules by having the overload on input only not the output so a 3 kVA brick can deliver the whole 3 kVA to one 55 volt leg which is a whopping 54 amp enough to melt extension leads. On any construction site you will get the extension lead plugged into extension lead plugged into extension lead it always happens how ever much one tries to train. And things do fall on the extension leads which cause shorts and they do go on fire.

When I was at University it caused a large debate should students be taught the normal way or the right way. Being taught in laboratory conditions does not train the student for the real world.

Personally I want to watch my back and I would want the central transformer with emergency stop buttons around the workshop in a training workshop so I can protect my students. If it was not a training workshop I would not include E-Stops. Again because a training workshop items using over 16 amp would be on 32 amp plugs. But out of the training environment I would likely try and get away with 16 amp plugs.

 

[ban-all-sheds]

Its a flooring training centre. So the sockets will be mounted in the students training bays.

So it's a place of work.

Basically you have to stop there - you cannot do the design for this and you cannot go out and start buying bits and pieces for an electrician to install.

Yes, you can have a 110V infrastructure installed which does not rely on portable 3kVA-for-some-of-the-time site transformers.

It's time for an electrician, to whom you should entrust every part of this.

 

[ericmark]

Its a flooring training centre. So the sockets will be mounted in the students training bays.

So it's a place of work.

Basically you have to stop there - you cannot do the design for this and you cannot go out and start buying bits and pieces for an electrician to install.

Yes, you can have a 110V infrastructure installed which does not rely on portable 3kVA-for-some-of-the-time site transformers.

It's time for an electrician, to whom you should entrust every part of this.

No it's not a place of work. Schools and collages do not need to follow the same rules. Only the teachers and lecturers are covered not the students and with places like schools and collages there are different rules. A lecturer is permitted to do things we would never dream of doing in industry.

Clearly the guy needs to know what to ask for. He has already said he not doing it as a DIY but wants to know what can be done and what to ask for. If he owns the school and is the sole employee he can near enough do what he likes. Wrong in my mind students should be protected by the same laws as workers.

There was a case where a firm sent a student to college where he was injured and it was the firm taken to court not the college as the firm was the employer and should have vetted the college.

 

[ban-all-sheds]

No it's not a place of work. Schools and collages do not need to follow the same rules.

I cannot find any evidence that educational establishments are exempted from the EAWR.

 

[mattysupra]

Thanks for replies, im asking the questions as i dont know what to ask for and what does what. Im trying to get knowledge of different systems, products etc so when the sparky is next in (next week as it happens) i know what to ask for rather than go on one persons advice of what they think is best. I have listened to many times in the past to "professionals" that simply dont understand what im asking for or they take teh easy route and fit a load of crap as it has more profit for them or its a "easier" job if they did xyz.

So im just trying to find out what is available and best agreed option between others (you lot)

The install WILL be done by a professional. We are a training centre that also covers H+S training so anything done here needs to be 100% with certificates / test results etc.