Me on the Motorhome Matt Podcast

[Admin]

 

[barryd]

My brain hurts.

 

[Nabsim]

Yeah I saw you Phil, interesting stuff I thought. Wasn't sure from the first one where they started looking at the problem exactly what it was but do now.

One thing I wasn't sure of from the vid (and it could just be me missed it), the adaptor that is mentioned that causes the problem, I take it that is the 3 pin to EHU adapter? If so are they all wired with earth to negative by default do you know? I will open one up myself and check but grounded at the moment so not got one to hand.

Personally not a problem for me as I only use the emu socket for the generator (or very rarely, site EHU), had it so that either or both of my 30A mains chargers can be used via built in 240V or external 240V sources since I gt the two Victron chargers.

In case anyone doest watch the vid right too the end it isn't just using power banks connected to EHU socket that may be unsafe but also if you connect at home with a 3 pin plug to EHU.

 

[barryd]

In case anyone doest watch the vid right too the end it isn't just using power banks connected to EHU socket that may be unsafe but also if you connect at home with a 3 pin plug to EHU.

Interesting. I never watched it all but I have a 3 pin plug to EHU adaptor which very occasionally if I am plugged into someones house or once or twice in a farm yard etc I have plugged into a domestic socket through a window.

I Got the impression though that the issue was because the powerbank is floating in that it has no ground but a house does doesn't it?

 

[Nabsim]

Interesting. I never watched it all but I have a 3 pin plug to EHU adaptor which very occasionally if I am plugged into someones house or once or twice in a farm yard etc I have plugged into a domestic socket through a window.

I Got the impression though that the issue was because the powerbank is floating in that it has no ground but a house does doesn't it?

What I took from it is its down to the 3 pin adapter wiring Barry, will let Phil answer your question, it is down to grounding. Watch the vid again

The power bank itself. is perfectly safe when used as intended, its only when you connect to ehu socket.

 

[edina]

Interesting. I never watched it all but I have a 3 pin plug to EHU adaptor which very occasionally if I am plugged into someones house or once or twice in a farm yard etc I have plugged into a domestic socket through a window.

I Got the impression though that the issue was because the powerbank is floating in that it has no ground but a house does doesn't it?

The house is a grid supply and is what the EHU point is designed for....I think
The problem is using a powerbank to the EHU.

 

[barryd]

The house is a grid supply and is what the EHU point is designed for....I think
The problem is using a powerbank to the EHU.

Thats what I thought but Neil above is suggesting otherwise. We need Phil to confirm.

 

[YeoBlade]

Has anyone died?

 

[Rosehip]

I watched that earlier - thought you were very clear but then MM would say something and confuse me again.
I don't trust elektrickery at the best of times, so if there is an issue with plugging in to EHU at home with a 3 pin I would like to understand what not to do

 

[Boris7]

Has anyone died?

Yes Millions of people have died, none due to this mind.

 

[trevskoda]

Has anyone died?

Who you gona call.

 

[colinm]

Has anyone died?

I've had a shock off a 3ph 415v supply and I'm still around to tell you it 'stung a bit', but I very much doubt anyone in their right mind would recommend it as 'safe'.

 

[MERL]

Better than the previous attempt but still not correct. Yes, with a power bank or inverter if your metal kettle develops a fault where the live makes contact with the metal body then nothing happens...no shock so a floating supply from a power bank would appear to be safer than a supply with the neutral and earth linked together. However if your toaster now develops a fault and the neutral connects to the metal body you now have 240v between the two appliances, if you touch both simultaneously you're probably dead.
If the neutral was bonded to earth like it is in our homes and the live touched the metal body then the MCB/fuse would trip/blow because there's a direct short between live and neutral, this is called the fault current path and our electrical regs focus on how quickly an MCB or fuse reacts and turns off under these fault conditions. This is why we have the earth linked to neutral in our homes.
If you only power one single item from a floating power bank or an inverter you're fine and effectively safer with the floating supply than with a grounded neutral, that's why we use isolating transformers to power razor points in bathrooms BUT those razor points ONLY power 1 item at a time and hence there's no risk of the double fault issue mentioned above.

 

[Wully]

Mmm my heeds spinning. I’ve plugged from the inverter in to the vans hook up point to run the aircon a few times so is this the same and I shouldn’t be doing that.

 

[barryd]

So one appliance good, two appliances not good but what about a normal hookup cable plugged into a house with a normal plug? I always assumed that was safe as its no different to being plugged into a hookup point is it? Just a different connecter surely.

 

[trevskoda]

Mmm my heeds spinning. I’ve plugged from the inverter in to the vans hook up point to run the aircon a few times so is this the same and I shouldn’t be doing that.

Yes dont do that.

 

[trevskoda]

I have 2 invertes in my van, one powers the fridge only, the other one powers a 3 pin socket for a smal plug in plastic 400w fan heater for warming van in winter untill the heater matrix kicks in.
As for ehu plug through the vans trips to charge batteries 24/7 and run a 1000w heater in deep winter which is on a time clock to keep her dry from damp.

 

[MERL]

So one appliance good, two appliances not good but what about a normal hookup cable plugged into a house with a normal plug? I always assumed that was safe as its no different to being plugged into a hookup point is it? Just a different connecter surely.

Yes, plugging your EHU lead into the house using a 15A to 13A adapter is essentially the same as plugging the EHU lead into the dedicated 15A circular socket on a site.
What's different is a power bank or inverter doesn't have one side of the supply tied to the earth terminal and the supply is floating with no live and no neutral, just a floating 230v supply.
The 'double fault' scenario is the major risk with a floating system. For it to occur you need 2 METAL bodied objects to develop the correct fault AND they need to be plugged in and powered up AT THE SAME TIME. And you need to touch them both at the same time. If these faulty items were used whilst on conventional hook up they'd trip out so in that sense your items are 'checked' so to speak whenever you use them.on conventional hook up.
You can see that you need a perfect storm to get killed, it's highly unlikely BUT possible and being shocked hand to hand is particularly dangerous because your heart is directly in the current path. Using double insulated plastic toaster/kettle combo removes the risk from those items.
I think I'm correct in saying that the Victron inverters actually bond one pole (the neutral) of it's supply to the earth via a relay when being used off grid. This is to retain the same safety designs behind our home mains systems. I've contemplated doing the same thing to my vans inverter setup but not got around to it and it's currently floating. I'm not unduly worried though because only my oven has a metal earthed body. I'm also a thrill seeking adrenaline monkey who likes living on the edge.

 

[molly 2]

My bluetti has an earth connection bolt ????

 

[Nabsim]

Yes, plugging your EHU lead into the house using a 15A to 13A adapter is essentially the same as plugging the EHU lead into the dedicated 15A circular socket on a site.
What's different is a power bank or inverter doesn't have one side of the supply tied to the earth terminal and the supply is floating with no live and no neutral, just a floating 230v supply.
The 'double fault' scenario is the major risk with a floating system. For it to occur you need 2 METAL bodied objects to develop the correct fault AND they need to be plugged in and powered up AT THE SAME TIME. And you need to touch them both at the same time. If these faulty items were used whilst on conventional hook up they'd trip out so in that sense your items are 'checked' so to speak whenever you use them.on conventional hook up.
You can see that you need a perfect storm to get killed, it's highly unlikely BUT possible and being shocked hand to hand is particularly dangerous because your heart is directly in the current path. Using double insulated plastic toaster/kettle combo removes the risk from those items.
I think I'm correct in saying that the Victron inverters actually bond one pole (the neutral) of it's supply to the earth via a relay when being used off grid. This is to retain the same safety designs behind our home mains systems. I've contemplated doing the same thing to my vans inverter setup but not got around to it and it's currently floating. I'm not unduly worried though because only my oven has a metal earthed body. I'm also a thrill seeking adrenaline monkey who likes living on the edge.

Merl take another look at the video, its at the end after the main discussion on it I think. The 3 pin socket Matt uses to connect his ehu socket at his house could give the same fault as the adapter on the power bank from what they said. To make this safe he is going to install a ground spike at the outside socket, this in effect then becomes the same as an on site EHU socket. You need to have another look as its a bit beyond me but from what I am taking fro it you haven't quite understood what they are saying.