A Beginner’s Guide to Using an Electrical Hook‑Up (EHU) on a motorhome

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Beginner’s Guide to Using an Electrical Hook‑Up (EHU)

Your new motorhome may well have come with an electrical hook up cable – your power lifeline!

Practical Motorhome magazine describes it as “an umbilical cord to civilisation”.

Plugged in it provides power for your appliances, fridge, lights, TV and a charge up for your leisure battery. And, a bonus, your 12v leisure battery isn’t depleted.

In today’s post, we explore

· What an electrical hook up is

· What you need to ensure a good electric hook up at your pitch

· How to connect up and disconnect safely from your pitch electrical bollard

· Some of the common pitfalls to watch out for when doing an electrical hook up

· The steps to go through if your electrical supply trips, and

· How electrical supplies might be slightly different on the continent and how you can overcome any potential issues

What is an electrical hook up?

An electrical hook up is an outdoor power socket that is rated at 16A or 10A supply in the UK, although on the continent it can be as low as 6A. Delivering 230V AC electricity via underground cables to a supply bollard within the vicinity of your pitch, these bollards can have two or more outlets, housed in waterproof posts. This post/bollard supplies you your power via connection on the side of your motorhome. Each bollard is protected by a circuit breaker and earth leakage devices.

Before You Start: What You’ll Need

1. A 16A blue or orange 25m long EHU cable (standard for UK and European sites). It has three round pin connectors at each end, one female and one male. (The male will plug into the bollard, the female into your motorhome wall socket)

2. The cable should be in good condition with no cuts, frays, or crushed sections. The wires inside it will be 2.5mm² in cross-section. Your lead should be CE-marked and must comply with BS EN 60309. You can expect to pay around £30 to £40 for a new power lead.

3. Potentially, for continental trips, have an additional 10m cable for those pitches where electric hook up bollards are far part – see later points

4. A reverse polarity adapter - a small cable adapter that you plug between your EHU cable and the bollard

5. A UK three pin plug adapter cable – if you want to charge your motorhome at home on your driveway from a household socket

6. A European 2 pin adapter socket for continental electric hook up bollards – see later points

7. Your motorhome’s onboard charger and RCD/MCB panel (usually inside the van)

Step‑by‑Step: How to Connect Safely

A. Park and level the motorhome

Make sure you’re positioned so the cable can reach the hook‑up post without stretching or where possible, without crossing roads.

B. Turn off everything inside the van

Switch off all appliances, heaters, pumps, chargers.

This avoids a sudden load when you plug in.

C. Connect to the motorhome FIRST

1. Uncoil the entire cable - A coiled cable can overheat under load. Uncoiling it from the drum allows any normal heat build up to dissipate – thus avoiding potential fires and damage to your motorhome electrics. TAKE THE OPPORTUNITY to check the cable for any nicks, crush points, frayed or exposed wires – see later notes

2. Check that your ’van’s RCD/isolator switch is turned OFF.

3. Connect to the motorhome FIRST - Plug the female end of the cable into your motorhome’s EHU inlet on one of the exterior wall sides. This prevents you from holding a live cable. Make sure you hear it click in place fully.

4. Raise the cover of the electricity outlet provided on the pitch supply bollard and insert the blue plug (male) of the supply cable (On some bollards you will need to turn it clockwise until it locks, on others there is a flick switch), please ask your site team if you need help. You should always carry out this procedure in that order, to avoid having to carry a power supply lead with a live connector to the motorhome.

5. Now you can switch your motorhome’s consumer unit – a RCD (main safety trip) and MCB’s unit (for sockets, charger, water heater etc). Once powered, your onboard charger will begin topping up the leisure battery.

6. On smaller sites and particularly on the continent - Insert a polarity tester into one of the three pin sockets in your motorhome to check all connections are correctly wired. See section 4 further down for more details

Safety tips: It is important you make sure your cables and equipment are maintained in good condition by simple checks every time you use it,

· Always fully uncoil your electric hook up cable

· If it is damaged – never cut, re-join or tape up. Never wrap any connection in polyethene sheets – condensation will form and it conducts live electricity! Always check the ends of the cable where it goes into the connector – an area where exposed internal wires often appear

· It is good practice to check the operation of the safety RCD unit before turning on your appliances by using its test button. If it fails to operate correctly – your system needs to be checked by a qualified motorhome electrical technician.

· If you have to connect your 25m cable to your 10m cable because a bollard is too far away, the connection between the two cables should be raised off the ground by the use of a propriety joining cover - a waterproof connector to join the two cables together safely – available from sellers such as Kampa.

· Note: If you are ever in any doubt about hooking up your motorhome, enquire at the site office, where the staff can advise.

Common Pitfalls to Watch Out For

Potential problems

Overloading the supply – forgetting about the electric hook up amp rating and drawing more current than it is rated for

A 16A supply is generous, but you can still trip it by running:

Electric kettle
Electric heater on high
Microwave
Hairdryer

…all at once.

OR - Using household appliances

Domestic kettles (2–3 kW) are notorious for tripping site bollards. A low‑wattage camping kettle or using gas is safer.

OR - Leaving the cable coiled

This can cause dangerous heat build‑up.

OR - Not fully inserting the plug

A loose connection can arc and damage the plug.

OR - Walking away without checking the bollard breaker

If the post is already tripped, you’ll think your van is faulty.

OR - Occasionally, your EHU might trip out because of an electrical fault, for example, because of a damaged hook-up lead or a blown fuse in the vehicle’s consumer unit.

Experienced motorhomers tend to regularly check their hook up lead and know which of their appliances they can operate at the same time and still stay within the limits of the supplied power. We have written a section about knowing your appliances power requirements further down the post.

How to Check for Reverse Polarity

Reverse polarity is more common in Europe than the UK, but it can happen anywhere.

What it means

Live and neutral are swapped at the bollard. Your modern motorhome, will in all probability, still work, but some appliances may be less safe because their internal switches may sit on the neutral side instead of the live.

How to check

Use a plug‑in polarity tester (cheap and tiny). Steps:

Plug it into a 230V socket inside the motorhome.
Read the lights - usually:

Two green lights = OK
One green, one red = Reverse polarity
Other combinations = Other wiring faults

If you find reverse polarity

Many modern motorhomes have built‑in protection.
If yours doesn’t, you can use a reverse‑polarity adaptor which you can purchase from many motorhome supplier shops OR
If unsure, ask the site warden—they often know which pitches have issues and which bollards may be correct polarity

Safety tips:

Never leave a polarity tester in the three pin sockets.
Don’t use the supply if the polarity is incorrect unless you are using a reverse polarity adapter

What Changes on a 10A or 6A Hook‑Up?

Some European sites – and a few UK CL/CS sites offer lower-amp supplies. On such sites you must ensure that the total rated wattage (rated power) of all your appliances and equipment switched on at any one time is less than the power supplied to you.

Here’s what that means in practice:

Supply	Max Watts	What You Can Run
16A	~3680W	Most things, but avoid running everything at once
10A	~2300W	Careful with kettles, heaters, microwaves
6A	~1380W	Very limited—use gas for heating & cooking
Typical appliances

TV 50W 0.2A
Fridge 125W 0.5A
Microwave 1200W 5.2A
Kettle (low wattage) 750W 3.3A
Battery charger 100W 0.4A
Hairdryer (low wattage) 800W 3.5A
Hair straighteners 150W 0.75A
Slow cooker 156W 0.6A

So, On 10A

A low‑watt kettle is fine
Microwave + heater together may trip the post
Use the heater on low or switch to gas

On 6A

Electric kettle will almost certainly trip it
Microwave may trip it
Electric heater must be on low (usually 500–750W)
Best approach: run almost everything on gas

Some basic mathematical ability helps here – you are reading a post written by a man who failed his maths ‘O’ Level five times – anyway, moving on – some basic maths knowledge allows you to calculate which appliances can run without tripping the cut-off.

Tips –

· Heating and air conditioning consume large amounts of electricity!

· If you have a dual fuel boiler – use gas for your heating when on a lower amp supply site

· You can buy a huge range of 12v appliances from motorhome equipment shops – helping you to stay within your wattage limits; also, great if you do lots of off grid touring and rely on your leisure battery power.

Motorhoming on the continent

· Generally, we have found that most of our appliances will work in Europe where a 220v supply is available. However, we have stayed on sites where the supply has been 10A or even 6A. On these occasions, appliances haven’t worked as well.

· Some continental bollards use an old style two-pin hook up and so you will need a European hook up adapter that plugs in between the end of your hook up and the bollard.

· Some bollards at sites on the continent are further than 25m away from our pitch – in which case – we have had to use our other 10m cable attached to the 25m one to reach the supply

If the Power Trips

What to do if your motorhome electric hook-up trips out

It happens – we have experienced it a few times on our travels. If your motorhome overload trips the EHU’s cut-off:

1. Check the site bollard first

Most trips happen here.

2. Then check your van’s RCD/MCBs

If your RCD trips repeatedly, unplug and investigate—don’t force it.

3. Reduce your load

Turn off high‑draw appliances and try again.

How to safely disconnect from your electric hook up bollard supply at the end of your stay

To safely disconnect from your hook-up, follow these steps each and every time:

1. Switch off all appliances and electrical equipment

2. Then turn your motorhome RCD/ isolator switch to the OFF position.

3. At the EHU post, press the release button and pull out the lead.

4. Disconnect the power supply cable from the motorhome.

5. Coil up your electric hook up cable – take the opportunity to check it over as you do so

NOTE: if you are leaving your pitch for the day only, it is tempting to leave your electric hook up cable connected to the power bollard as a marker for an occupied pitch! DON’T DO IT! Firstly, it isn’t safe and will disrupt the correct routine for connecting up your power supply when you return. Secondly, chances are you will return to find it nicked!

Final Thoughts

Using a hook‑up becomes second nature very quickly. Most motorhomes are well‑designed for both 16A and lower‑amp supplies, and once you understand your power limits, you’ll be able to camp comfortably anywhere.

However, it is worth remembering these simple electrical safety tips to ensure a safe and faff free trip: