230v breaker ratings

[Monarch-of-the-Glenn]

**DIY'ing a campervan, trying to plan the electrics myself before getting help to install so I understand what is going on under the hood. (Engineer by trade, can't help myself)

Questioning my basic understanding of circuit breakers and plug sockets: If a standard plug is rated to 13A, do you just multiply the number of sockets on a circuit to reach your breaker size? If so a 16A breaker would only accomodate 1 socket?

In a campervan situation whereby you're less likely to be doing multiple things at once, if you lower the breaker rating is the worst that happens the breaker trips and you tell your girlfriend to stop streaming football while you blow dry your hair?

cheers
(1st of many posts I expect)

 

[littlespark]

It doesn’t work like that.

You can have as many sockets on the circuit as you wish… the TOTAL load is what gets plugged in. It’s just each plug can be up to 13A…. Very few loads are.
Even a kettle at 2.5kW is about 11A

A camper van hook up is generally only 16A anyway…. For the whole van.

My advise is to consult a dedicated van conversion engineer. There will be standards for the wiring which will be different to BS7671 that we in general work to.

In my experience, with a touring caravan… the 230v mains powers the general sockets, for plugging things in…. And a battery charger for the 12v leisure battery.
The 12v leisure battery runs all the lights.

 

[Lister1987]

It's worth noting Section 721 of BS7671 covers electrical installations within caravans and so you may wish to consult that, in addition to any other knowledge you garner.

 

[littlespark]

Yes i should have said motorhomes may have standards in addition to BS7671.

There's also the gas and water sides of it to look into as well.

 

[Monarch-of-the-Glenn]

So in a house, how would you estimate a likely load?

In a practical sense it's relatively straightforward in a van, don't use 2 hair dryers at once.... but I'm interested in the principles.

Do the codes/regs have rule of thumb tables for number of sockets on a loop for instance?

 

[littlespark]

The assumption is... you cant use every socket, all at once... and in somewhere like a house its the fact that most appliances are portable, and you may want to use them in different places.... therefor as many sockets as you want, and less trailing extension leads that can be tripping hazards.

Years ago, it was one or two single sockets in a bedroom... now it could be 3 or 4 doubles... The amount of actual load hasnt changed much... in fact, might have decreased... but its the design of the circuit that matters.

We also have fuses in our plugs to protect each appliance... but a circuit for sockets could most likely be a 16A radial... ie one branch from the consumer unit supplying a number of sockets.... or a 32A ring... where the cable loops around each socket and returns to the consumer unit. Balances the load across 2 paths to any point of use, and increases the total load that could be used on a circuit.


Its unlikely the sockets in a campervan will be on a ring. one or two radials, at 16A each would suffice.
Again, im comparing to a 6 berth caravan... so maybe a bit bigger than what youre working on...
The 16A is sized to protect the cable going out to the sockets... which is maybe only 1.5mm flex rather than domestic grey flat twin and earth...
Typical load... and these wont all be on at the same time... we have a kettle, toaster and hair dryer.. thats the biggest things.
Our hob has one electric hot plate ring, and 3 gas rings... but again, hardly used. The oven and grill is gas.
The fridge is triple sourced... it can be run from mains electric, off the battery or off the gas....
Heating and hot water is gas, but there will be an electric ignitor through a controller.
Other electric loads is just the TV, and whatever phone chargers the girls bring.... but we have 12v aux sockets fitted as well as 230v so phone chargers can be plugged in there through a car adaptor.

We have a 230v outlet accessible from outside the van too, but i just plug in fairy lights to decorate the awning.

(sorry... i mean to say "mythical, winged, little person" lights)

 

[Lucien Nunes]

As per @Littlspark, Ignore the number of sockets - having lots of sockets is a matter of convenience of location rather than an indication of electrical consumption.

In a house, where the electrician has to design the circuit to suit all normal modes of use, there are rules-of-thumb indicating what fraction of an appliance's rated load can be expected to be required by typical occupants at any time, known as diversity. Lots of loads infrequently used add little to the expected total, because it would take a black swan event for them all to be switched on together. However, in a camper, the loads are likely to be known in advance and you can actually mark ke a reasonable estimate of the usage,

But then you have that overriding limitation of the hookup. If it's 16A, there's nothing more to be done breaker-wise, as you can't go above that and don't need to go below. In some places you won't even get 16A, more like 10A or even 6A. My boat has a 10A limit on the shoreline when on its home mooring, although it's wired for 16A as that is sometimes available elsewhere.

However I have the option to switch-in a specially re-calibrated 10A breaker that trips slightly lower than the one in the cabinet, so that overload will trip it first. A hard fault would probably trip both together though.

tell your girlfriend to stop streaming football while you blow dry your hair

Don't blow dry your football! Or most other kinds of balls. Cool wash only, do not iron. Always read the label.

 

[littlespark]

So that’s the difference between Iron Man and the Iron Lady?….. Iron balls?

No sorry. I’m getting my jokes mixed up
Snow…. It snow..