Air Care System + Shower Trip

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I have a rather strange problem to do with an air care system (Vent-Axia) currently installed in the loft. We had this system installed to reduce humidity in the house after condensation was building up on the windows.

A few years ago we installed an electric shower, a Triton model with a remote heater (installed under the bath) and a control plate on the wall. After this was installed every time the air care system was on and the shower was then turned on the main RCD would trip. After a while we realised that turning the air care system off solved this little problem.

However I would like this air care system to work again. Today I moved the control panel next to the air care system and spurred the system off the upstairs ring main (previously it was a spur off the lighting circuit) through an FCU. However this also tripped the main RCD.

Next I did a few diagnostics and turned off all the circuits in the house apart from the upstairs ring main and the shower and unplugged all the appliances in the house, this didn't trip the circuit! So I gradually turned on all the circuits again and it held. I then began to plug in all the appliances and I found the offending unit to be my computer. So I left this unplugged from the socket. However, tonight with the computer unplugged I decided to take a shower and it tripped the RCD again! So even though my computer + shower + air care system tripped it, it seems that there is something else causing this.

I should note that my computer + shower causes no problems what so ever. Additionally I should point out, even though this is quite common, the lights dim when the shower is used. The shower also comes on for a brief period but trips when the lights reach their dimmest point.

Any insight to what could cause this would be greatly appreciated.

Many Thanks.

 

[stem]

Small leaks on several circuits can add up and be enough trip the RCD. If you search this forum, you will find that IT/computer equipment is often "leaky" & can cause tripping (even if not faulty) add this to small leaks on other equipment such as your aircare system and shower then that could be enough to cause a trip.

You really need to have the suspect circuits/equipment checked and if they are in spec, if they are you could consider fitting them to separate circuits with individual RCD's

Lights dimming when a shower is switched on is not unusual, and does not necessarily indicate a problem. In fact most people experience it.

 

[rssteve]

should that heater be under the bath tho?

 

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Yes it is suitable for use under the bath. The installation instructions say it can be placed either under the bath or in the attic.

I'm not sure about the "leaky" equipment, originally I thought this might be the problem, but it trips as soon as the computer is plugged in, not while it is turned on. But I will investigate this. It also doesn't account for the fact that it still tripped while the computer was unplugged. I did the same thing again last night and it tripped with the computer unplugged again.

 

[ericmark]

I would guess on neutral earth rather than line earth fault. As more current is drawn the voltage between neutral and earth increases so the fault will not trip when low consumption but will with high consumption and since most items do not switch neutral could be anywhere. It's a get out mega job.
Eric

 

[Synapse]

Just discovered something else.

Starting with all of circuits off apart from the air-care, shower and downstairs ring main. I started to turn some circuits on as I did previously. Now I've found that it's tripping with either the upstairs or downstairs lighting, it's probably easier to display the combinations that work in a list.

Note: This is with all other circuits on also.

#1
Shower = ON
Air-Care = ON
Downstairs lighting = OFF
Upstairs lighting = OFF
Downstairs Ring Main = ON

#2
Shower = ON
Air-Care = ON
Downstairs lighting = ON
Upstairs lighting = ON
Downstairs Ring Main = OFF

 

[ericmark]

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Image

Earth Leakage

• ericmark
• 12 Aug 2008
• 1

Earth Leakage

• ericmark
• 12 Aug 2008
• 1

These two pictures show how with a leakage to earth there all the time the current draw can effect if over or under 30 ma is drawn. The only way to find which circuit has the neutral earth fault is to use a insulation tester switching each circuit on and off will produce the same effect as the neutral is not switched. Hope this shows you the problem. Also hope it works as first time I have tried to upload any pictures Well slight fault the first one with all switches closed should have shown over 30 ma I must have forgot to run multi sim before copying image sorry.
Eric