Room on wheels- electrics???

[Chippynotsparky]

Hi I am building a conference room on wheels, the purpose of this is to be mobile. I wanted just one plug coming out to power the room. Inside I would like to have 4 plug sockets built under the desk, and 2 plug sockets in the roof. The cables will be built into the walls and I am concerned with the option of „Daisy chaining“ multiplugs. So how would I make 2 separate areas for plugs join into one plug to power the room? What equipment do I need. I’m my head I wire two multiplugs into one plug and add a fuse somewhere

 

[Rockingit]

I don't have my regs to hand to refresh my memory of specifics, but generally speaking the best practice way of doing this would be a small consumer unit (a garage style 3-4way one) with RCD to provide a lighting feed and then a sockets circuit which if it's just small and low numbers a single radial system. Feed this from a 16a or 32a ceeform inlet bolted to the outside.

 

[timhoward]

Further to what @Rockingit said which I agree with, I have a feeling this will be what the regs calls a special location, which describes various things that have extra rules.
It sounds to me as though section 717 "Mobile or Transportable Units" will likely apply to this conference room on wheels.
If it does, then it doesn't change the basic idea of having a consumer unit, some circuits inside, and a safely detachable supply.
It does change however change the type of cable used and the way it's earthed. Possibly other things but those are the two I remember!
Consulting someone who has the regs book is advisable.

 

[Lucien Nunes]

OP - you give your location as Berlin. Is this being made to meet UK regulations, German ones or both?

By 'on wheels' do you mean on a motor vehicle?

 

[Chippynotsparky]

OP - you give your location as Berlin. Is this being made to meet UK regulations, German ones or both?

By 'on wheels' do you mean on a motor vehicle?

hi sorry, its made in berlin to german regs i guess. its a wooden structure on caster wheels but still mobile or transportable for sure

 

[Chippynotsparky]

Further to what @Rockingit said which I agree with, I have a feeling this will be what the regs calls a special location, which describes various things that have extra rules.
It sounds to me as though section 717 "Mobile or Transportable Units" will likely apply to this conference room on wheels.
If it does, then it doesn't change the basic idea of having a consumer unit, some circuits inside, and a safely detachable supply.
It does change however change the type of cable used and the way it's earthed. Possibly other things but those are the two I remember!
Consulting someone who has the regs book is advisable.

thanks so much, just trying to ge my head round it to save another thousand multiplug scenario

 

[Chippynotsparky]

I don't have my regs to hand to refresh my memory of specifics, but generally speaking the best practice way of doing this would be a small consumer unit (a garage style 3-4way one) with RCD to provide a lighting feed and then a sockets circuit which if it's just small and low numbers a single radial system. Feed this from a 16a or 32a ceeform inlet bolted to the outside.

thanks, i had a similar suggestion elsewhere. just got this drawing through as well. what do you think.

 

[timhoward]

hi sorry, its made in berlin to german regs i guess. its a wooden structure on caster wheels but still mobile or transportable for sure

Thanks @Lucien Nunes and apologies @Chippynotsparky , I do usually check the location but your username sounded so British!

 

[timhoward]

Trying to give non-country-specific advice:
LED lighting will draw almost nothing so if there's a lower fuse that 15amps available I'd use it. (If it was UK, we'd be using double pole protective devices to interrupt hot and neutral.)
It's worth check local requirements regarding earthing.
It's worth thinking about what/where will have GFCI protection. Ideally faults outside would be reset at the point of supply to the mobile unit or at the consumer unit in the mobile unit. Arranging for a fault outside to not trip a GFCI in the main building requires some planning in consultation with local regs.

Hopefully you'll get some more specific help with local requirements!

 

[Lucien Nunes]

Just got this drawing through as well. what do you think.

Specifically for America, and arguably not correct practice there either.

I do not know what you have against daisy-chaining socket-outlets. It is the normal way to connect them.

What is the source of power that is going to feed this room? Will it plug into the wall with a Schuko plug or something bigger? What appliances are going to be used inside - is there an electric heater?

 

[pc1966]

You seem to have a USA background in terms of the example currents/voltages/wire-by-gauge references.

UK and EU building supplies will be 230V nominal, i.e. using a blue "commando" connector such as this for the inlet:

247.1693 | Scame IP66, IP67 Blue Wall Mount 2P + E Right Angle Industrial Power Plug, Rated At 16A, 230 V | RS

uk.rs-online.com

However, for building sites and similar it is common to have 110V (yellow version of that connector - not interchangeable) from a centre-tap transformer or generator so 55-0-55V for less risk of electric shock. Comparable with USA practice of 120-0-120V supplies for any 240V loads, fed with linked double-pole breakers.

For 110V applications you normally need double-pole breakers for that reason, as both live conductors can produce a high fault current to earth/ground.

In the UK 230V is usually single-pole over-current protection in the line/hot wire only, but for caravans, etc, you must have double-pole RCD for shock protection (so neutral/cold is simultaneously interrupted with L on a fault).

In the EU it is often double-pole over-current protection as they have historically not had the close-to-ground neutral the UK has had, nor have they always used polarised plugs & sockets (so L/N can be swapped by plug direction) so frequently appliances will have protection in both L & N.

TL;DR - you need to be sure of where your power will come from to get the right voltage to begin with!

 

[Lucien Nunes]

We're in danger of overthinking this. I understand it to be a kind of mobile conference quiet-zone booth that can be positioned in an office, as he describes it as wooden and on castors.

As with any electrical installation, the design depends on what electrical equipment needs to be powered although some of it is fairly obvious, A few laptops, the video conference equipment, lighting, a fan or two and at a push, a Nespresso machine.

The total load is likely to be below 16A and it could plug into the office wall socket with a Schuko plug, aggregate earth-leakage permitting, This means the whole setup is basically a posh extension lead, which does not need a distribution board. If it is protected at source with a 16A MCB, there is no point putting any 16A MCBs within the unit. It is common practice to use 16A circuits for lighting in EU, so there may be no need to fuse anything down below 16A either.

The two caveats with supplying it from a Schuko plug are the lack of polarisation, requiring any switchgear that is used to be double-pole, and the functional leakage. If there is a full rack of VC equipment and/or an expectation of multiple desktop computers in use then the leakage might be quite a few milliamps. I don't know whether there are now regulations in Germany stipulating the maximum functional leakage that should be passed through one plug and socket outlet, as there are in the UK. If there are, and the leakage is likely to exceed the limit, then connection to the supply via an EN60309 plug would be needed. OTOH a self-contained VC unit, a TV, a sound bar and a few laptops would probably. be fine on a Schuko.

This reminds me I must brush up on current German regs, I am 30 years out of date.

 

[pc1966]

We're in danger of overthinking this. I understand it to be a kind of mobile conference quiet-zone booth that can be positioned in an office, as he describes it as wooden and on castors.

Yes, re-reading the thread and it looks like an indoors display, so many of the concerns are less of an issue and it is, as you say, more of an extension block on steroids.

In that case it is probably powered off a 16A Schuko socket somewhere in EU, or a 13A socket if in the UK. It might still be an idea to use a 16A commando inlet and then have some extension cables made up for use different locations though, instead of a long trailing lead that might need a plug/socket adaptor to be used in addition.

As transportable and probably likely to flex a lot, I would also suggest it is wired in flexible cable such as H07RN-F (with ferrules on the ends!) to reduce the risk of cable faults from vibration induced movement cracking conductors. While it is not an area I normally deal with, I seem to remember that is in UK regs for caravans?