Economy 7 tripping when all heaters and immersion are on

treborssenni · Feb 24, 2015

I live in a park home, it has off peak storage heaters and off peak bottom element on the hot water tank. If I just have the three heaters on[elnur 2x1.7 and one 900w combination with convector] it normally works fine although it has tripped once. But if all are on plus the immersion the main off peak switch trips. I thought it may be the immersion but I have replaced it and it still trips. So now all appliances are new, the immersion must start heating the water as it is warm [but not hot] I have had an electrician in to test but he cannot find a fault,could the trip be to sensitive? it is always the main trip and not the individual ones.

ifindoubtdont · Feb 24, 2015

I have 5 holiday homes in Wales and I regularly experience something similar.Which CU (fuse box) did the electrician test at, the one in the park home or the one immediately outside. Which one trips, inside or outside. If it's the RCD that is tripping, a Ramp test will find out how sensitive it is. If it is then it's quite straight forward to change for an electrician. Park/Mobile Homes usually run on 16A mcb's so it's not surprising it trips (2x1700w + 900w = 4300w) if a 20A mcb is fitted then it should be just ok, but switch a kettle on or the immersion kicks in then it will trip, and we haven't added the lights, tv, fridge/freezer, radio alarm etc yet. Do you need all that heating on at the same time, if not shut off rooms you don't use. Have you got LPG gas central heating, if so use that, it works out about the same as electric, just turn down the radiators in rooms not used. Hope this helps.

Paul.M · Feb 24, 2015

By the sounds of it your RCD is tripping. After quite a few "trips" it can become more sensitive (or faultly/not doing the correct function). A little test you can carry out yourself is to unplug everything in your house and just turn on the immersion heater, see if that trips it by itself? Now plug in your fridge and see if it trips??

It may be an over sensitive RCD and tripping out with what we call accumulative earth leakage. Ask your electrician to prform a "ramp mA test" to see what it trips out at and cross reference those readings against an "earth leakage clamp meter" under normal household electricial load/running. This will narrow it down......ps I bet it's the fridge