RCD Protection Question......

[Taylortwocities]

A 10mA RCD in series with a 30mA one? Pointless, IMO.
The 10mA will only trip if the leakage current is more than 10 and less than 30mA. An earth leakage of more than 30mA will trip one, or the other, or both.
The reason 30mA is chosen is to reduce the potential of your heart going into fibrulation in teh event of a shock situation.
The RCD that you have is providing protection for all of the sockets in your house, and that means all the people in your house too.

Don't buy a 10mA RCD just to make you feel safer mowing the lawn. Have an electrician run an RCD tester on your 30mA RCD, and then you'll know the whole family will be protected in the event of something going wrong.

 

[telectrix]

sorry mate. i disagree. 10mA through your body is far less painful than 30mA. the discrimination may be an issue. give you that. also, given the fact that 90% of RCDs aren't even tested with the test button more than once in a blue moon, i stand by my post.

 

[Pete E]

sorry mate. i disagree. 10mA through your body is far less painful than 30mA. the discrimination may be an issue. give you that. also, given the fact that 90% of RCDs aren't even tested with the test button more than once in a blue moon, i stand by my post.

To add to that, I'll mention the bit about my grandson again...In the event of an accident, I'd much rather an RCD trip at 10mA than nearer 30mA..

I know no system is perfect, but for the small cost of the RCD outlet, I don't think I have anything to loose.

Just had a quick look in the garage, and I can add an FCU into the existing cable run very easily and then drop a short length of cable to the new RCD socket....Another advantage is that the location of the RCD will negate the need for me to use an extension lead....

 

[Midwest]

The Beama RCD Handbook is a good read for those long windy rainy nights. Page 11 gives some guidance of the effects of electricity on the human body.

 

[Midwest]

PS I can't see how anyone can get tingles for a Class II insulated lawnmower wearing suitable protective gloves, footwear, eye & ear protection, hi vis vest & safety helmet?

Been doing it in flip flops & shorts, have ya!

 

[Spoon]

PS I can't see how anyone can get tingles for a Class II insulated lawnmower wearing suitable protective gloves, footwear, eye & ear protection, hi vis vest & safety helmet?

Done be silly.... You don't need all of that stuff, just a faraday suit..... oh.. and some wellies..

 

[Deleted member 26818]

As Murdoch says. Its worth getting the rcd tested electrically and also get the earthing checked. A rcd will not operate correctly if the earthing is not adequate, since it measures an imbalance via "earth leakage" current.

Sorry but that is just not true.
An RCD will operate if there is no earthing at all.
In fact most electrical garden equipment uses 2 core flex with no CPC.

 

[Deleted member 26818]

Many years ago, I attached active RCD plugs to all my tools which could possibly cut through the power cord.
Whenever I use one of the tools,I would test the RCD plug.
That way I would not be relying on any RCD or RCBO installed in the CU that may or may not have had the test button pressed.
Personally I believe individual RCD sockets are safer than a single RCD/RCBO protecting the circuit, as they are more likely to be tested at each use than any in a CU.

 

[davesparks]

A rcd will not operate correctly if the earthing is not adequate, since it measures an imbalance via "earth leakage" current.

An RCD detects imbalance between line conductors or between line conductors and neutral and trips once a threshold has been exceeded. It doesn’t measure anything

 

[HandySparks]

When you say you tested the RCD you mean the ‘T’ button on the RCD? If so, it only tests it mechanically.

Not true. On every RCD that I'm aware of, it's an electrical test. Done using a fixed resistor between incoming line and outgoing neutral (or vice versa) to create the current imbalance required. It's likely to be at a higher current level than the rated trip differential current, so it's only an indication that the RCD is still functional rather than an accurate test of sensitivity.