Electrical setup for catering trailer

[Mick Mac]

Hi all.

I'm converting an old horsebox into a catering trailer & have got to the stage where I need to add plug sockets & switches. The most power hungry item of kit I have is a 900W water heater which forms part of my handwash water system & which, I think, requires a 13amp fuse. I also have 3 fridges (2 x 300W & 1 x 240W) which I believe each need a 3amp fuse.

The rest of the electrics are for interior & exterior LED lights & a few spare plug sockets for charging phones & a bluetooth speaker / radio.

I was wondering if anybody can direct me as to the type of Consumer Unit that I need, what kind of RCD & MCBs it should contain & finally the kind of weatherproof, surface socket I should get as the exterior inlet?

I need to be able to connect to a mains supply where available & a small LPG generator when I'm off the grid.

I'm very new to this kind of thing so if I've left out any important details please let me know & I'll provide anything I can.

Thank you in advance.

Michael

 

[mwatsonxx]

& finally the kind of weatherproof, surface socket I should get as the exterior inlet?

That comment shows your electrical knowledge is inadequate for this type of installation. The use of a catering trailer brings with it very heavy responsibilities and serious consequences if something goes wrong.

 

[Mick Mac]

Thanks for your reply & you're absolutely correct, I have no experience of this kind of thing, hence the original query. I'm trying to fully cost the installation with a view to purchasing all of the equipment & then hiring an electrician to install everything. I'm trying to do as much research & prep work as I can myself to both keep costs down & give me a better understanding of the installation.

 

[winston1]

The most power hungry item of kit I have is a 900W water heater which forms part of my handwash water system & which, I think, requires a 13amp fuse. I also have 3 fridges (2 x 300W & 1 x 240W) which I believe each need a 3amp fuse.

No, fuses in plugs are to protect the cable, not the appliance.

Fridges often have switch on surges which would blow (incorrectly) fitted 3 amp fuses.

 

[mwatsonxx]

I'm trying to fully cost the installation with a view to purchasing all of the equipment & then hiring an electrician to install everything.

It's never a good idea to supply the electrical kit because you lose out on the installers guarantee. Only your electrician can specify what's required and a couple of quotes cost nothing. You can always come back here for any guidance on the quotes and/or his design intentions.

 

[winston1]

I'm trying to fully cost the installation with a view to purchasing all of the equipment & then hiring an electrician to install everything. I'm trying to do as much research & prep work as I can myself to both keep costs down & give me a better understanding of the installation.

Why. Part of an electricians profit is buying at trade price and marking up the price. You won't get it as cheap as (s)he will so no benefit in you buying it, but you might buy the wrong bits.

 

[Mick Mac]

I appreciate the advice from both of you. I've contacted a handful of electricians this afternoon but none of them are able to carry out work on a mobile unit to be used for commercial purposes. I've been advised that this type of work requires a specific certification which not many electricians seem to carry. I'll continue searching on Monday, cheers again

 

[ericmark]

I would say the fridge is the first thing to sort out, as so much will hinge on this.
I have seen fridges designed for boats and caravans with compressors, but in the main they use absorption fridges which are rather inefficient, but can be triple supply selecting 12 volt, 230 volt or gas. The big thing these fridges don't have a large start current. I looked at the idea of fitting a compressor freezer into a caravan, my idea was to use a STC-1000 temperature controller so I could select 4°C or -18°C however we swapped caravans so it was never done.

The uncertainty is how a standard compressor will stand being moved, clearly compressors are used in motor vehicles that's how we get air conditioning units, however every domestic fridge/freezer I have bought says it should be left 24 hours after being located, what I don't really know is why. And you would not want the unit to fail of course.

As to inrush you can now get inverter driven fridge/freezers so would guess you can also get inverter driven fridges, the commercial type are very different to domestic, but with both the inrush is reduced.

The other question is what regulations require for the units? I know with a caravan placing a few freezer packs in the fridge will keep it cold for quite a long trip without need to connect up the 12 volt, but I am not selling stuff from my fridge. You may find you need monitoring to show nothing got too warm. I know with my freezer at home, if there is a power cut it shows the highest temperature reached before the supply was restored, then back to normal once door has been opened.

The old non inverter fridge/freezer when plugged into an energy meter hits around 10A at start, but run is under 1A so with two old style you will need to start them one at a time. So likely you will need a generator able to give something like 3 kW if using old type fridges, but half that with a inverter fridge, and most of that would be for the water heater.

Generators with large flywheels will likely take the in rush, it also depends on how they are regulated, but inverter generators may not be able to rev up fast enough when a freezer tries to start, however they make less noise so it would be better if you could use that type.

This is why I say get the fridge worked out first. The Peltier fridge is really useless for what you want, either absorption or compressor, with a compressor fridge you need around 3 minutes between switching off and back on again. As far as I am aware you can't get absorption freezers, so if you need a freezer then has to be compressor, I did see one cool box type Peltier freezer, but rather rare.

 

[ban-all-sheds]

The most power hungry item of kit I have is a 900W water heater which forms part of my handwash water system & which, I think, requires a 13amp fuse. I also have 3 fridges (2 x 300W & 1 x 240W) which I believe each need a 3amp fuse.

So you aren't selling hot food?

I've contacted a handful of electricians this afternoon but none of them are able to carry out work on a mobile unit to be used for commercial purposes. I've been advised that this type of work requires a specific certification which not many electricians seem to carry.

Hmmm.

 

[big-all]

no expert at all but horse box to a hygieneic food preparation unit ??
you need to meet with hygiene standards with preparation and storage areas complying to get a food catering certificate before you can trade
are you aware off the need to comply with hygiene requirements ??

 

[JohnW2]

So you aren't selling hot food?

Is that perhaps where the LPG comes into play (as well as powering a genny)?

Kind Regards, John

 

[flameport]

I've been advised that this type of work requires a specific certification which not many electricians seem to carry.

Not true, however plenty of electricians will not want to do that type of work for various reasons.

In addition to the usual requirements of any other electrical installation, section 717 applies.
There is a lot more involved than just selecting the correct consumer unit.

 

[EddieM]

Hi all.

I'm converting an old horsebox into a catering trailer & have got to the stage where I need to add plug sockets & switches. The most power hungry item of kit I have is a 900W water heater which forms part of my handwash water system & which, I think, requires a 13amp fuse. I also have 3 fridges (2 x 300W & 1 x 240W) which I believe each need a 3amp fuse.

The rest of the electrics are for interior & exterior LED lights & a few spare plug sockets for charging phones & a bluetooth speaker / radio.

I was wondering if anybody can direct me as to the type of Consumer Unit that I need, what kind of RCD & MCBs it should contain & finally the kind of weatherproof, surface socket I should get as the exterior inlet?

I need to be able to connect to a mains supply where available & a small LPG generator when I'm off the grid.

I'm very new to this kind of thing so if I've left out any important details please let me know & I'll provide anything I can.

Thank you in advance.

Michael

Maybe a company such as this could provide some advice. Though I suspect they'd just want to do the whole job.

 

[Robin0577]

Not true, however plenty of electricians will not want to do that type of work for various reasons.

In addition to the usual requirements of any other electrical installation, section 717 applies.
There is a lot more involved than just selecting the correct consumer unit.

Depending on the nature of use, it's quite likely that parts of BS7909 (Requirements for temporary electrical installations for entertainment and related purposes) would apply as well as BS7671

 

[ban-all-sheds]

Is that perhaps where the LPG comes into play (as well as powering a genny)?

I took that to mean that there was an LPG generator, nothing else.

I accept that that may have been wrong.

I will stop thinking about how mistaken I was to not wonder why someone would use LPG for a generator if they had no other need for LPG, because there's someone over there who wants to give me my coat...