Recent content by Marvo

20 years ago power fail regularly damaged VFD's, nowadays nearly all drives are designed to survive a complete unexpected power outage. Usually somewhere in the 600 page, 14 language manual it will state a limit to the frequency of power outages the drive is capable of handing and where I am we...

The frequency gauge will indicate grid overload if it falls below 50Hz for any length of time without correction being applied. This will indicate that supply side demand has outstripped generation capacity and I'd expect they have a plan for this where they'll immediately shed some large...

I've never owned one of those fancy MFT's. I've always been fan of kyoritsu test gear which I think is branded as Kewtech in the UK and I've got several testers I still use regularly in the workshop that are well over 20 years old and still accurate and reliable. Teh clamp/volt meter has...

I would absolutely agree with that sentiment Murdoch.

It's possible to profile and identify electrical loads by characteristics such as their current over time, their inrush current, the phase angle, noise spikes, duration, frequency of reoccurance, functional earth leakage currents present and power factor to name but a few. Basically by looking...

Is there a particular reason you did the live leakage test? You say the leakage is roughly equal from your new installation and the original installation so it's not cause by a single culprit and depending on the circuits and equipment connected I wouldn't consider 150-170mA leakage as...

I'd be more worried about there could be two separate equipotential zones within touch distance of each other. I'd definately suggest you get an electrician in to assess the situation.

IT equipment with switch mode power supplies can cause common mode noise. Depending on the capacitive value of the EMC filters and any PFC circuitry and the frequency of the noise it can cause RCD/RCBO's to nuisance trip and this tripping tendency can be amplified if it's a ring final circuit...

Looking at the state of the copper conductor it looks like that cable was cut whilst it was live....

Getting back to VDE tools just very briefly I couldn't resist buying these. I can throw one in each of my non-VDE socket sets and declare that they're now VDE rated. :)

With that kind of Ze reading the Ra of the actual rod on its own could be far higher so I wouldn't waste time trying to find it. You could spend hours searching so I'd rather spend the time just installing a new one and getting a better impedance value.

Can't you use a resin joint and a meter of HO5 or HO7RNF cable and just extend it?

I see from a different thread you said you were working for a customer...... Are you an electrician working at a customers premises or is this wiring in your own house?

That's not a meaningful test. You need proper test equipment which is expensive and not easy to use so I'd suggest getting an electrician in and pay him for an hour to do some tests just to confirm the circuits are safe. He'll also be able to advise you much better as to how urgent it is to...

Is there actually a supply earth connected to the earth bar or is it just CPC's from the final circuit cables?