Waste disposers I've fitted all had a grooved rubber ring with a clamp to fit the disposer to the sink waste. So there wasn't any electrical link between the sink and the disposer body (other than moisture). It may be that not all disposers are mounted like this but many are.
Edgar
Spot on. My SS sink is not earth bonded - and the waste disposal unit is simply plugged into a ring main socket that is beneath the sink.
As my entire house is now RCD protected I don't have a socket that is not. Obviously this is only a problem since I had the CU unit fitted because before that I didn't have all the sockets protected by RCD.
My garage is attached to the house and has never had a separate mini CU.
I use the pressure washer at the front of the house via a socket in the garage - and at the rear of the house (cleaning the patio for example) via an external waterproof socket that is simply a spur from inside the house. Switching on the pressure washer for the first time from either of these sockets will trip the RCD.
I do have a mini CU in my garden shed and, thinking about it, when I clean the patio in the spring I may use an extension lead from the shed and plug the pressure washer into that. Hopefully, if the washer still trips the RCD - it will only be the RCD in the shed that trips, rather than the ground-floor ringmain RCD in the house.
I wonder if, when using the pressure washer at the front of the house, I used a 'plug-in' RCD in the garage socket, whether that RCD would trip rather than the 'house' RCD - saving me having to reset all the various cooker clocks etc? Perhaps worth a try. I presume there is no problem with using a plug-in RCD with a ring main already protected via RCD?
I suspect that the house RCD will still trip.
There is no problem with using a plug in RCD on a RCD protected socket, however there is no real advantage either, since cascaded RCDs typically have no mechanism to discriminate - once the trip threshold is reached - one or both can trip.
If you sneak up on it with the ramp test on a RCD tester - i.e. gradually increase the leakage until you get a trip, you my find that one always goes before the other (although there is no way in advance of predicting which if they both have the same trip threshold). However if you simply apply a leakage that is over their trip threshold, then its anyone's guess as to what combination of trips you get.
Chances are however that assuming there is not a particular fault on the pressure washer itself, then the house CU RCD will trip before the plug in one, this that is seeing the combined leakage of all the house appliances as well as whatever the pressure washer introduces, whereas its dedicated one will only be seeing its leakage.
The fault may be not directly related to the appliance that apparently causes the trip.
----------------------------------------- The other thing that occurred to me is that the problem could be at the switch. The two pumps are controlled by a light switch (though not off a lighting circuit), one of a panel of switches. As the RCD only protects the garden circuit it isn't a major issue if it trips.
Chris R
OK - I'll just try it and see! I'll probably be using the pressure washer in the next week or so to wash all the accumulated salt out from underneath the car.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.