240v earthing

[mart143]

hi guys
im just about to fit 240v consumer unit to my van
what i would like to know is do i need to earth the consumer unit if so where do i earth it to ?

[GBBiker]

Are you using a power take off and invertor or just an RCD and hook up lead?


You cannot earth to the vehicle body due to the negative earth system on the van.


If you are using an RCD and hook up lead, just earth the case through the lead.


IME, the best option if you are using an invertor is to use a separate earth spike.

[mart143]

we will be using RCD and hook up lead
what amp breaker do i use for sockest (we will be using 12v volt lighting only so no need for breaker for thoes )

[jerry2]

I reckon 10amp max m8.
That way you don't overload the site supply.

[GBBiker]

I presume you will be running a kettle and water heater at least. You will need a 32A RCD. Even a travel kettle will blow a 10A

[fickladwivatranny]

Are you using a power take off and invertor or just an RCD and hook up lead?


You cannot earth to the vehicle body due to the negative earth system on the van.


If you are using an RCD and hook up lead, just earth the case through the lead.


IME, the best option if you are using an invertor is to use a separate earth spike.

The consumer unit earth terminal must be connected to all exposed metalwork which includes the body of the van. The negative earth of the 12volt system will have no effect in interfering with the 240volt side but it is ESSENTIAL that the correct earthing arrangements be made. It is paramount also to have an RCD fitted in your van (either integral to the consumer unit or separate) as it cannot be relied upon that the site supply will be RCD protected - particularly small farm CL sites whose buildings and outdoor sockets are often wired in wet string.
The RCD must be capable of withstanding the highest load you will be using in your van. Often, a 16amp plug and socket arrangement (blue BS4343 type industrial) is used and this should be the type you will find on a site. Therefore, an RCD of a rating at least 20amp will suffice. There must also be overcurrent (overload) protection provided in the form of MCBs for each circuit in the van. This is necessary as the RCD will not provide overload protection - only earth fault protection. The highest rating of MCB must therefore not exceed the 16amp rating of the supply plug and socket.
It is interesting to note that on many older sites, the rating of their sockets are only 5 amps. On more modern sites, they are often 10amps and on some recently wired sites, they have 16 amp supplies. So as long as you allow for the 16amp arrangement, you should be fine.

[ake]

Well said, Not really a fick lad are you

[grotbag]

I'm looking at buying a portable hook up cable and wiring, which looks like an extension lead. The kit is 50 quid and from a reputable camping shop, not one of the home made ones you can get from ebay for a fiver!!

The kit itself has 3 sockets built in to it, and it can be wound up and stored in one of the lockers when not being used. Has any one used one of these before and would I need to earth it when in use, or would the site supply already be earthed?

Cheers

[pippin]

How will you take the lead out of the van?

[ake]

The site supply SHOULD be earthed but there are no guarantees

[grotbag]

How will you take the lead out of the van?

Stick it out the window!!

Been looking at some proper kits at the local shop today and think I'm going with a more permanent install now. Will be more practical and look a lot tidier as well.

Have now got under way with the start of my conversion and will try and get some photos up soon. Watch this space!

[mart143]

so i do need to earth the consumer unit to the van body then ???
some say yes some say no ?????

with the van having no metal toutching the ground i would have thought the consumer unit did not need earthing to the body
but hey im no sparky so all advice would be gratefull

[fickladwivatranny]

so i do need to earth the consumer unit to the van body then ???
some say yes some say no ?????

with the van having no metal toutching the ground i would have thought the consumer unit did not need earthing to the body
but hey im no sparky so all advice would be gratefull

There are two types of earthing here that serve two different purposes. The main earth terminal in the consumer unit must be connected to the earth wire in your hook up lead. This will be done through the larger pin in the blue plug. This is your MAIN earthing conductor which you will rely on for protection from short circuits and overloads.
The van body must also be connected to the earth terminal in the consumer unit. This is known as a BONDING conductor. This will ensure that, in the event of a fault, the van body cannot become live under fault conditions. This in itself is not providing an effective means of earth as you have 4 big chunks of insulating rubber material between van body and earth. Therefore, it is there only for your (and other's) protection. Do not dismiss this though as it forms a MAJOR part of electrical safety. Especially when you consider that any wires can easily become damaged when in contact with metalwork through vibration etc.
Providing you follow this advice, you should have a safe electrical installation in your van. As far as there being an unreliable earth on a site, well it is possible. Therefore, as you are relying solely on the earth wire in your hook up lead for your main earth, and, you do not know if it is reliable, you should upon first connecting the van to the electrical supply on a site, press the "test" button on the RCD to establish it's correct functioning. If it does not trip, then it suggests either a faulty RCD (do not use it - get it confirmed) or a lack of main earthing conductor. When you press the test button, there is a temporary fault placed to earth and the fault current flows along the earth wire and trips the RCD. If the earth is not present, it should not trip.
There are also devices available to plug into a socket which will confrim if earth is present and also warn of other faults such as reversed polarity (live and neutral wrong way round) or even if the neutral is missing. Such devices are made by "martindale" and others, available on fleabay for less than a tenner!

Hope this helps!!!