Voltage Surge (1 Viewer)

[Ditcha]

I used one of these picked it up of ebay for £60 easy to fit https://uk.farnell.com/furse/esp-240-16a-bx/surge-protector-16a/dp/2470173

 

[Pausim]

Can anyone confirm that the AVS30 switches both live and neutral? It seems like a basic requirement since much of Europe doesn’t have polarity rules.

 

[Greenway]

Those who know about these things, could this be used as an alternative?

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[TCG]

So here I am, nit-picking again. For any newbies looking at this, the 'MH Intake' should be a male connector, and the connector on the wire going into it should be a female. Male connectors have exposed pins.
Your description is correct but the picture is wrong.

yes you are nit picking..

 

[Pausim]

Those who know about these things, could this be used as an alternative?

This ones seems to be only 15A per phase and since we only use one that might be a bit limiting.

 

[GPW]

Did you notice the red text?. "The neutral line will not cut off when the product cut off the power". Which suggests that (something we all should check anyway) that it will be useless IF the EHU was reverse polarity. Something to think about?.

What difference does it make?
It's not an personal safety device it's a 'stop my stuff being fried by too many volts' device.

Can you name a single device today that exposes the Neutral or Live wire to a person?
Everything today is double insulated or earthed, one pole is fine. For day-to-day faults the RCD does both poles.

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[PeteH]

What difference does it make?
It's not an personal safety device it's a 'stop my stuff being fried by too many volts' device.

Can you name a single device today that exposes the Neutral or Live wire to a person?
Everything today is double insulated or earthed, one pole is fine. For day-to-day faults the RCD does both poles.

Bearing in mind it is a lot of years since I studied "Electrotechnology". And time has moved on (a Lot).

My thinking is, In a reverse polarity situation, as can be found regularly still, on some continental sites. IF the voltage spike is not detected on the "neutral line", Because UK wiring does not have double pole switching. It would then be theoretically possible for the "spike" to reach the parts it should not?, In which case the "delicate bits" would be fried before the device operated, it being on the "neutral" line effectively when reversed, and therefore after the potentially fragile devices being protected?. It could be why the red text was there as a warning?.

Probably someone with much more recent experience, will come along and tell me if my theory has legs, but having spotted it I thought it was worth noting?.

 

[Richard n Ann]

Bearing in mind it is a lot of years since I studied "Electrotechnology". And time has moved on (a Lot).

My thinking is, In a reverse polarity situation, as can be found regularly still, on some continental sites. IF the voltage spike is not detected on the "neutral line", Because UK wiring does not have double pole switching. It would then be theoretically possible for the "spike" to reach the parts it should not?, In which case the "delicate bits" would be fried before the device operated, it being on the "neutral" line effectively when reversed, and therefore after the potentially fragile devices being protected?. It could be why the red text was there as a warning?.

Probably someone with much more recent experience, will come along and tell me if my theory has legs, but having spotted it I thought it was worth noting?.

With a break in the neutral (or anywhere) there can be no current flow. So no damage can be done.
Unless of course the voltage spike is many thousands of volts, then it can jump the contacts

Edit: reading your post again. It depends how it detects the spike. Would have thought it detects the difference between L and N.... Or N and L same difference .

 

[Pausim]

With a break in the neutral (or anywhere) there can be no current flow. So no damage can be done.
Unless of course the voltage spike is many thousands of volts, then it can jump the contacts

Edit: reading your post again. It depends how it detects the spike. Would have thought it detects the difference between L and N.... Or N and L same difference .

Not sure it is looking for differences between L and N, unlike RCDs, so much as voltage variations. My concern would be that if the circuitry includes diodes etc it might only be monitoring the L side.

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[PeteH]

Not sure it is looking for differences between L and N, unlike RCDs, so much as voltage variations. My concern would be that if the circuitry includes diodes etc it might only be monitoring the L side.

I have similar thought. And was why I raised the point that the seller had thought it necessary to highlight the fact in red?.

 

[autorouter]

Did you notice the red text?. "The neutral line will not cut off when the product cut off the power". Which suggests that (something we all should check anyway) that it will be useless IF the EHU was reverse polarity. Something to think about?.

For those with any interest in this, it is possible to convert a single-pole device to double-pole by adding a 2-pole contactor.
https://uk.rs-online.com/web/p/prod...VgrTtCh1DEQI3EAQYASABEgKgSvD_BwE&gclsrc=aw.ds
A contactor is a power relay, that is an electrically controlled switch. It has six terminals. Live in and live out, neutral in and neutral out, as you would expect. Also A1 and A2 control terminals.

When A1 and A2 are connected to Live in and Neutral in, it will switch both poles off when either live or neutral are switched off. The one in the link will clip onto the rail inside a consumer unit and is easy to mount. Of course it's better to just buy a double-pole device in the first place, but if that's not possible then this is a way to convert it.

 

[GPW]

Bearing in mind it is a lot of years since I studied "Electrotechnology". And time has moved on (a Lot).

My thinking is, In a reverse polarity situation, as can be found regularly still, on some continental sites. IF the voltage spike is not detected on the "neutral line", Because UK wiring does not have double pole switching. It would then be theoretically possible for the "spike" to reach the parts it should not?, In which case the "delicate bits" would be fried before the device operated, it being on the "neutral" line effectively when reversed, and therefore after the potentially fragile devices being protected?. It could be why the red text was there as a warning?.

Probably someone with much more recent experience, will come along and tell me if my theory has legs, but having spotted it I thought it was worth noting?.

On the continent the earth systems are often different and can be unrelated to L & N - the wires that actually provide the power. For this protection earth is completely irrelevant and not even connected to the switch. Earth is simply a safety wire and carries no power.

ALL power is transmitted along both L and N wires. If any does leak out via a 3rd route your RCD switches you off. That's what the RCD is for.
There IS no polarity, it is alternating as Nikola Tesla designed it!
L or Line/Live is only more dangerous in the UK as Neutral is closer to earth.

The voltage protecting device simply measures the AC voltage between L & N just as if you stuck a multimeter (on an appropriate scale) onto L & N yourself. Then if it's out of range it immediately switches or stays off.

Think of it as a miniature robot looking at a multimeter ready to switch off your 'van's power at a moments notice, as surrounding vans start overheating and going wrong. If you have 'auto-switch over to inverter' you may not even notice. That's the main danger of being too smart, you could be sitting quietly watching 'Only Fools and Horses' on DVD blissfully unaware of the catastrophy unfolding in the nearby bays.

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[autorouter]

On the continent the earth systems are often different and can be unrelated to L & N - the wires that actually provide the power. For this protection earth is completely irrelevant and not even connected to the switch. Earth is simply a safety wire and carries no power.

ALL power is transmitted along both L and N wires. If any does leak out via a 3rd route your RCD switches you off. That's what the RCD is for.
There IS no polarity, it is alternating as Nikola Tesla designed it!
L or Line/Live is only more dangerous in the UK as Neutral is closer to earth.

It's not just on the continent. Building sites in the UK use a special 110 volt AC supply. There is no Live and Neutral. The two poles swing from -55 to +55 volts, in a kind of see-saw fashion so that when one is +55V the other is -55V, so that the difference between them is 110V. The idea is that no wire is ever more than 55 volts from the ground. Most healthy people like builders will not be injured by a 55V shock, in almost all circumstances.

The 'reverse polarity' problem is related to the fact that in most 240V mains supplies, one pole is connected to earth at the point of supply, so the other pole is dangerous to touch. In the UK the systems are designed assuming you know which pole is dangerous. On the continent they design systems so that they are safe whichever pole is dangerous. If you wire a motorhome like a UK house, then plug it into a continental house, you can expect some safety issues.
And there's still plenty of motorhomes with no RCD.

 

[PeteH]

On the continent the earth systems are often different and can be unrelated to L & N - the wires that actually provide the power. For this protection earth is completely irrelevant and not even connected to the switch. Earth is simply a safety wire and carries no power.

ALL power is transmitted along both L and N wires. If any does leak out via a 3rd route your RCD switches you off. That's what the RCD is for.
There IS no polarity, it is alternating as Nikola Tesla designed it!
L or Line/Live is only more dangerous in the UK as Neutral is closer to earth.

The voltage protecting device simply measures the AC voltage between L & N just as if you stuck a multimeter (on an appropriate scale) onto L & N yourself. Then if it's out of range it immediately switches or stays off.

Think of it as a miniature robot looking at a multimeter ready to switch off your 'van's power at a moments notice, as surrounding vans start overheating and going wrong. If you have 'auto-switch over to inverter' you may not even notice. That's the main danger of being too smart, you could be sitting quietly watching 'Only Fools and Horses' on DVD blissfully unaware of the catastrophy unfolding in the nearby bays.

If you are OK with it that is fine by Me. I noted that the Manufacturer, had seen fit to highlight the fact that the Neutral was (in theory) unprotected. And flagged it up. That is all I need to do. As you observe there is no "polarity" in AC, however the convention is applied (maybe erroneously?) to UK wiring. Ie. Brown is often referred to as Live, and Blue as Neutral. In fact I think there is a recent "new" wiring colour convention just to complicate matters too. We used to have red/black/green, then Brown/Blue/green-yellow.

 

[GPW]

If you are OK with it that is fine by Me. I noted that the Manufacturer, had seen fit to highlight the fact that the Neutral was (in theory) unprotected. And flagged it up. That is all I need to do. As you observe there is no "polarity" in AC, however the convention is applied (maybe erroneously?) to UK wiring. Ie. Brown is often referred to as Live, and Blue as Neutral. In fact I think there is a recent "new" wiring colour convention just to complicate matters too. We used to have red/black/green, then Brown/Blue/green-yellow.

I think we have to be realistic about use cases here.
The only danger would be if
a) it had just tripped (disconnecting Live only)...
b) ... and you were connected to a site where neutral was 'live' wrt earth
c) ... and you started licking the connected neutral terminals of some appliance that was plugged in

In practice you either just wait or switch off the main EHU breaker.

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[Wissel]

Interesting thread and something I've not considered before

I suspect my EHU setup is very different to most peoples here, as it only powers my charger. But, as my charger is quite expensive, it would make sense having this type of protection.

You can buy them here:


For a tenner, it would be rude not to.

My consumer unit already has polarity checking and a switchover inside. When I connect to EHU, I connect the lead without switching the RCD on, then I can see the polarity before anything is powered.

If the polarity is correct I switch the RCD, if not I flick the changeover then flick the RCD (did it this way so if I am connected to a reversed polarity source I can see it's wrong before power reaches anything in van, plus I don't have to use one of those switchover leads). Nice and simple.

I'm wondering, as there is no chance of reverse polarity with my system, could I get away with just using the above protection?

I'd wire it between the switchover and RCD.

 

[berni109]

Here is a question for all u bright electrical people.
Would the following in a suitable enclosure be just as good as the device originally suggested @ a quarter of the price?

The technical details of the original dont say what the cutoffs values are that I can see.
So do u think the standard defaults on this alternative(?) would provide sufficient protection. U can tweek the values but I expect that u would have to set them up each time u applied power - cant see that your setup would be retained once power disconnected.
TIA
Bern

 

[SpeedyDux]

Thanks for this info, I had never heard of these before. I am fed up of unplugging during thunder storms.. I will get one of these and fit asap.

Currently I have an extension lead with surge protector. All my sensitive stuff gets plugged into this. It will be nice to get rid of that 6 gang socket.

I doubt if ordinary electronics can survive a lightning strike very close by. I'm in the unplug everything and keep fingers crossed tendency. At least a PVC acts as a Faraday cage.

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[GPW]

Here is a question for all u bright electrical people.
Would the following in a suitable enclosure be just as good as the device originally suggested @ a quarter of the price?

The technical details of the original dont say what the cutoffs values are that I can see.
So do u think the standard defaults on this alternative(?) would provide sufficient protection. U can tweek the values but I expect that u would have to set them up each time u applied power - cant see that your setup would be retained once power disconnected.
TIA
Bern

Nice little device, does current as well so you can dial in something below the site trip.

It does say: "Cut off in 1s if over volatge, under voltage or over current. "
so it's not super fast (I.e. not a substitute for an MCB) but I don't see why it shouldn't work. Maybe they mean 0.1s, but for overvoltage <1s should be enough to prevent stuff being fried. If your voltage nips up to 300V say it's the seconds after seconds after seconds turning into minutes that do the damage.

Lightning surges are a different thing, too fast for anything to react for a cut-off but surge suppression in general can help. For those belt + braces group there is always stuff like this:



This is a good thread, making me (us all) think about how our EHU systems and inverters work and can be safe and protect the van too.

 

[autorouter]

Here is a question for all u bright electrical people.
Would the following in a suitable enclosure be just as good as the device originally suggested @ a quarter of the price?

The technical details of the original dont say what the cutoffs values are that I can see.
So do u think the standard defaults on this alternative(?) would provide sufficient protection. U can tweek the values but I expect that u would have to set them up each time u applied power - cant see that your setup would be retained once power disconnected.
TIA
Bern

The product in @scotjimland's link has protection against lightning spikes as well as starting transients, which as @GPW says are too fast for this unit to respond.

The technical details were further down in the spec list, but to save you looking:
4.1.2 Rated current: 1A-63A (adjustable) (default: 40A)
4.1.3 Under-voltage action switch-off value: 210V-145V (adjustable) (default: 170V)
4.1.4 Over-voltage action switch-off value: 230V-300V (adjustable) (default: 270)
The default voltages look OK, but it depends on any special requirements, for computer or medical equipment, for example.

I would hope the settings are retained when power is disconnected, but the spec doesn't actually say it so maybe they are not.

Note that it definitely needs an MCB (micro circuit breaker) in series with it:
"This product shall be combined with micro circuit breaker to play a role of short-circuit protection; otherwise, the product may not be able to realize load limit protection in case that input or load end of the product appears short circuit."

 

[MisterB]

As a non sparky - would a household type surge protection device work, similar to that required for latest 18th edition ? They are double pole protection?

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[GPW]

As a non sparky - would a household type surge protection device work, similar to that required for latest 18th edition ? They are double pole protection?

I don't see why not. You want ideally something in there, Lenny recommeded a good solution (the AVS30, see below). There seems to be 2 issues:

1. Fast spike from lightening somewhere
2. Voltage surge that fries your electrics

I suspect 2. is enough for most cases, the trick is finding space for it. A single pole is fine, you simply want to stop the circuit when it's out of acceptable voltage limits. I bought the one from my 19th Mar post above and will try to fit it to my Globecar, although a larger distribution box may be needed.

For simplicity you can wire something like this in

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[berni109]

Have a look at what I posted earlier in the thread and the replys. Fitted both to my van had room for 1 in the consumer unit and got another small din enclosure.
Do they work - who knows but not had any problems with electtricky so perhaps they do. Dont have the test equipment to find out but u set the volts and amps and it retains them.

 

[MisterB]

Nice little device, does current as well so you can dial in something below the site trip.

It does say: "Cut off in 1s if over volatge, under voltage or over current. "
so it's not super fast (I.e. not a substitute for an MCB) but I don't see why it shouldn't work. Maybe they mean 0.1s, but for overvoltage <1s should be enough to prevent stuff being fried. If your voltage nips up to 300V say it's the seconds after seconds after seconds turning into minutes that do the damage.

Lightning surges are a different thing, too fast for anything to react for a cut-off but surge suppression in general can help. For those belt + braces group there is always stuff like this:
http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=183657856726


This is a good thread, making me (us all) think about how our EHU systems and inverters work and can be safe and protect the van too.

So fitting the two items in a seperate enclosure that is wired in BEFORE the standard circuit breakers MIGHT provide more protection than currently exists (excuse the pun)?

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[GPW]

So fitting the two items in a seperate enclosure that is wired in BEFORE the standard circuit breakers MIGHT provide more protection than currently exists (excuse the pun)?

The units can look after themselves so yes they can be ahead of the MCB. If they are behind it doesn't hurt either as the MCB may trip on a spike, relieving the pressure but in practice I doubt it makes any difference.

I just have the over/under cutoff device for mine, for the 1 in 10000 chance of usage I'm confident it's going to help me a lot more than not having it. Actuall fitting it would also probably help, I'll have t get around to that LOL.

A more embedded option is to install a Victron inverter/charger which does the surge/boost/buck detection and switches over when required, but I'm uncertain how that will interact with the Electroblock charger in my Globecar, which would need disabling.

With the Victron you could be watching (a 240V) TV and never even notice as the surge arrives, it diverts for inverter mode and then disappears, and it switches back.

 

[MisterB]

The units can look after themselves so yes they can be ahead of the MCB. If they are behind it doesn't hurt either as the MCB may trip on a spike, relieving the pressure but in practice I doubt it makes any difference.

I just have the over/under cutoff device for mine, for the 1 in 10000 chance of usage I'm confident it's going to help me a lot more than not having it. Actuall fitting it would also probably help, I'll have t get around to that LOL.

A more embedded option is to install a Victron inverter/charger which does the surge/boost/buck detection and switches over when required, but I'm uncertain how that will interact with the Electroblock charger in my Globecar, which would need disabling.

With the Victron you could be watching (a 240V) TV and never even notice as the surge arrives, it diverts for inverter mode and then disappears, and it switches back.

Which victron inverter charger would be suitable? Swift bolero 2008. I am in the process of fitting a sterling 60amp B2B (when i can bend down a bit more) and will in time fit solar.

 

[GPW]

Which victron inverter charger would be suitable? Swift bolero 2008. I am in the process of fitting a sterling 60amp B2B (when i can bend down a bit more) and will in time fit solar.

Depends what your 240V power requirement is. I have a Victron Multi 500 in a vehicle thats good for 500VA (375W IIRC), it's there to run a fridge and odd other things. Bigger than they you run into cost and engineering decisions..
I.e. if you want to plug in a kettle or hair drying when off EHU you'll need a bigger one.

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