EHU is a simple utility application for campers and caravanners who want to take the guesswork out of connecting appliances to electrical hookup (EHU).

Set up your appliances before you travel, then all you need to do when you arrive at site is choose the level of hookup at your pitch.

EHU calculates the current draw of each appliance and displays a power bar that shows the total usage for different combinations. Worried about boiling the kettle while the fan heater is on? EHU can provide the information you need to avoid tripping the circuit.

Supports hookups of 6A, 10A and 16A at 230V, plus one user-configurable supply current between 1A and 15A.

Maximum cable current can be configured as 10A or 16A in Settings.

Screenshot of main view of EHU application

EHU is designed for iPhone and iPod touch but will run on iPad. Requires iOS 5.

Now available on the UK app store.


Custom Supply Current

The most common EHU supplies of 6A, 10A and 16A can be selected directly on the EHU page.  From version 1.1.0, there is also a custom supply current that you can use to configure the application for other supply currents from 1A to 15A.

To change the custom current to another value, select it, then tap it again. Select the required supply current using the selector wheel.

To hide the selector wheel, tap the custom supply current again, or hit the Done button. Note that changes to the custom supply current value are only saved if you press Done rather than Cancel to leave the page.

Maximum Cable Current

Most EHU cables for tent use are protected internally by a 10A miniature circuit breaker (MCB). This limits your supply to 10A, even if you are on a 16A hookup.

If you select a supply current of 16A on the EHU page, you may notice an information banner at the bottom of the page advising you that your supply is limited by your EHU cable.

You can configure the maximum supply current of your cable in the Settings application on your device.

If your cable supports 16A or more, set it to 16A. If your cable has a 10A MCB, set it to 10A. If your cable is limited to something other than 10A or 16A, please let me know with a comment on this page and I will incorporate it into an update.


6 thoughts on “EHU

    • Thanks for your interest in EHU. The app is written for the iPhone but, like all iPhone apps, does run on iPad. From iOS7, Apple greatly improved the way these are displayed on the larger screen.

      The reason there isn’t an iPad specific version is that there isn’t really enough going on to fill the iPad screen. I did try a mockup but there was a lot of unused space and no benefit compared to the iPhone layout.

  1. Instructions would be useful please for a novice iPad user. I have downloaded it successfully but can,t get further than first screen. Help,, Sue Oap.

    • Hello Sue,

      When you first run EHU, the first screen will be empty. You need to tell it about the appliances that you plan to take away with you. So press the + button in the top right corner and a new page appears where you can enter details. You’ll need to know the power of the appliance, which is usually on a small label somewhere, measured in Watts, e.g. 1000W. Let’s say you have a hairdryer that you want to take away and the label says it is 1200W; the details you need to enter are “Hairdryer” for the name and 1200W for the power. You can probably leave the description blank, unless you have two hairdryers that you take away and you want to distinguish them, e.g. “Morphy Richards” and “Babyliss”.

      When you have entered the details, press the Done button in the top right corner and the hairdryer will appear in the list of appliances. Repeat for your other appliances.

      When you arrive at site, they will tell you what power your hookup is. Press the EHU button in the top left corner and select the power of the hookup. You can select the most common values of 6A, 10A or 15A using the bar at the top, or scroll the numbers up and down if the supply is unusual. Press Done to get back to the list of appliances.

      Now you can check whether turning on different combinations of appliances will overload your supply. Just press the on/off buttons next to each appliance and watch the bar at the bottom.

      That’s pretty much all there is to it. Remember it’s only a guide to save you adding up in your head. Let me know if you are still having problems.

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