Food trailer electrical wiring

[akash_7869]

Hi.
I have purchased a food trailer and doing some work to change it according to my requirement. I need some help in electrical wiring. My load would be about 3.5kw most of the time and at times may go up to 5kw. I dont plan to go above 3.5kw but i have tried the wiring so that in future if the need arise then i dont have to re wire the internals. The wirings are done above the need to minimise future cost. So what i have done is connected a 63amp ceeform socket to 100a switched consumer unit. I further have 1x32amp rcbo connecting 4mm ring final for sockets. 1×16amp rcbo for lighting and low power exhaust fan.
My concern is :
1. Is it ok to have a 63amp ceeform with 100a switched consumer unit connected with 16mm cable though i may only have 32 amp supply at most of the time? I will use 63amp to 32 amp socket converter most of the time for 32a supply. Is this ok with electrical certification such as practices etc to have a large cu with less amp suppply?

Will this have any impact in certification?

I would really appreciate some insight and guidance from the experienced members.

Thank you

 

[paulears]

Lots of my work involves power supplies using all sorts of combinations, and if you ask multiple sparks - real ones, not entertainment folk like me, you get different answers, depending on their knowledge of commercial rather than domestic electrics and how what you want to do impacts on the current version of the regs. I get the same issue when we turn up with gear fitted with one capacity connector and the venue or event has different.

The arguments they make come up often. You have equipment that requires a certain current. Having a 100A switched consumer unit makes sense - the capacity is over your anticipated load. The key feature is that your cable size must be adequate for the maximum load. So must the circuit protection - so if the mcbs are suitably rated, and the 63A inlet on the trailer to the consumer unit is OK - then that part is not going to be an issue for anyone to test and sign off - or satisfy people wanting to test it. what seems to annoy people is the use of adaptors up and down in capacity. So a cable with 63A female connected to 32 male is a problem for some people. The connectors are not fused, so if your supply is able to handle 32A and is protected at that capacity, then the 63A connector on the trailer with your less than 32A consumption is OK. People seem to get jumpy because the cable could be connected to a device that would try to draw more than 32A - the limit of the other connector and then the protection would sever the feed. I've been quite happy with this system, and have racks with 63A male surface mounted blue inlets. I have adaptors from 63 to 32, and from 32 to 16, and 16 to 13A My job is to make sure I don't attempt to take too much. These step down adaptors are really common. everyone has them in a case somewhere. The arguments against are that accidental overloading might occur and the lowest circuit protection might fail - melting cables, with potential for fire. My counter argument has always been that circuit protection failure can happen, and cable failures are indeed possible, but risk assessable. I've always been more worried when drawing smaller currents from very capable supplies. Like needing 16A but having protection at say 125A. Clearly you could use 2.5mm2 cable to feed your trailer from a 125A ceeform, if you were stupid and if you went over that cable's capacity, then the supply would not trip and the cables would melt or catch fire.
So for me - I am happy with step down adaptors. Your up to 32A equipment load, with a 63A connector trailer end, going down a size at the supply but using 63A capable cable would be perfectly fine for me. 63A/16mm H05 or H07 would keep me happy - as long as the circuit protection at the supply end was functional and tested.

I'm happy working like this and my equipment shows me the current and voltage so I can monitor it. In my industry - we use distros - a box that might have a 63A male connector on it, and then it contains the mcbs to connect to 32/16/13 amp capacity. Single phase and 3 phase versions are common. Conversations routinely go "have you a 63 single stage right?" the answer might be "no - we've got 63-3 right and 32 single left - and you just pull out the necessary adaptors - a red 63 to blue 63, or 63 blue to 32 blue - whatever is needed. The only thing important is the upper limit. If they on ly have 32 and you need 40, then you use the cable set and simply reduce the load. I've also discovered a few converted venues where they have large capacity socketry - but with much lower than usual mcb ratings. A 16A outlet protected at 10A - that kind of thing.

 

[WaveJumper]

I would also perhaps get someone on board now who is actually going to sign off and certificate the installation before shelling out any more money on your build. If you intend on trading at events etc they are going to want to see all you H&S docs .

And just as an after thought many a food retailer I’ve seen at events have been using both electric and gas unless you taking along your own generator you’d obviously want to make sure your power requirements are not out of ‘the norm’ for the type of venues you may wish to attend. From my own experience venues organisers love to charge ridiculous amounts for plugging into a supply.

 

[fisicx]

There was a long discussion here a while back about electric food trailers and the conclusion was that generators were often forbidden at outdoor venues.

 

[paulears]

One of the big tours doing U.K. theatres was being hit with astronomic electricity usage charges by one chain, so they bought a touring generator. Their charges then had a generator parking charge added!

seriously though, the kind of places catering trailers turn up at is quite similar to entertainment electricity requirements and while bigger or more modern places have electricity available outside, there’s also a new rule set in play. Supplies of electricity outside now have very strict rules, especially where councils are involved. They all have them. Stuff like this.




Any electrical equipment used at the event must be in a safe condition and be suitable for that type of use (such as in the open air where it may be subject to wet weather). Rubber matting should be used to protect cables from weather and to prevent tripping.

Electricity can cause serious injury or death to performers, workers or members of the public if the installation is faulty or not properly managed.

When designing an installation Consider...​

• The location of any existing overhead power lines or buried cables
• The total power requirements for the site
• Access to a network power supply
• The use of generators
• Earthing
• Positioning of temporary overhead or underground cables
• The location of the stage(s)
• The main isolators controlling the electrical supplies to stage lighting, sound, special effects, emergency lighting and lifting equipment
• The location of mixer positions
• Special power supplies for certain equipment (example: imported from US)
• Power supplies required for portable tools etc
• The electrical requirements for emergency lighting and exit signs
• Power supplies for catering, first-aid posts, control room

All electrical installations and equipment must comply with the Electricity at Work Regulations 1989.

A temporary electrical installation report should be completed before any event commences.