Is a surge protector required on live and neutral or just live?

euser1984

Hi,
I'm getting an electrician to install main surge protectors on the fuse box which are about 50 euro each. He rang two suppliers - one is saying you only need it on live and the other is saying neutral as well.

Can anyone here advise?

Thanks a mill.

meercat

what brand?
any links?
is it the cartridge type?
generally live in one side
earth connection other side

your electrician should be able to confirm though

westom

euser1984 wrote: »

He rang two suppliers - one is saying you only need it on live and the other is saying neutral as well.

That question could not exist if 'how a surge protector works' was understood.

Destructive surges seek earth ground. Some protection systems have no protectors. But every protection system always has the only item that absorbs energy harmlessly. Earth ground. That connection to earth must be as short as possible.

The neutral wire should have a short connection to earth. A connection required by codes for 'human safety'. A connection that must be made even shorter (and no sharp wire bends, no splices, not inside metallic conduit, etc) so that it also does 'transistor safety'. Then that wire has best protection.

Other incoming AC wires cannot connect to earth directly. Those wires also must have a 'just as short' connection to the same earth ground. A protector does that earthing. Connect other AC wires also low impedance (ie 'less than 3 meters') to single point earth ground. Unfortunately, the connection cannot be made by a wire. So the connection is made via a protector.

If the above 'what a protector does' was understood, then his question would not even exist. Protection means every wire (both wires inside a telephone cable, satellite dish, etc) connects just as short to the same earthing electrode. Because no protector does surge protection. Because protection means either a protector or a dedicated wire connects to where hundreds of thousands of joules will harmlessly dissipate.

Protection is always about where energy dissipates. Any protector is only as effective as its connection to and quality of that single point earth ground. An earth ground (not the protector) should have most of the electrician's attention. Because only a single point earthing system does the protection.

M cebee

i think for standard tn-c-s

it's only the phase/line

M cebee

waste of time asking suppliers what to do anyhow:pac:

they don't know

euser1984

meercat wrote: »

what brand?
any links?
is it the cartridge type?
generally live in one side
earth connection other side

your electrician should be able to confirm though

It's the type that goes into the fuse board - he's not 100% sure as he wouldn't do surge protectors like this often. The guys in the suppliers said "neutral"

That's all the info I have I'm afraid.

M cebee

no offence:pac:-but suppliers will put your head spinning if you start asking them what to do

same as kitchen fitters and the rest

euser1984

Considering it is a domestic setup and I have only a general understanding of how electricity works if there is a surge where could it come from and what exactly is a surge? Increase in voltage? Amps?

Thanks.

2011

euser1984 wrote: »

Considering it is a domestic setup and I have only a general understanding of how electricity works if there is a surge where could it come from and what exactly is a surge? Increase in voltage? Amps?

Thanks.

It could come from lightning striking a power line outside.

euser1984

2011 wrote: »

It could come from lightning striking a power line outside.

Ok so it can come through the neutral cable then seeing as that is on the power lines?

westom

euser1984 wrote: »

Ok so it can come through the neutral cable then seeing as that is on the power lines?

Already answered.

Destructive surges seek earth ground. ...
The neutral wire should have a short connection to earth. A connection required by codes for 'human safety'. A connection that must be made even shorter ... so that it also does 'transistor safety'. Then that wire has best protection.

Every wire must connect to single point earth ground before entering. Every. Even the neutral wire. Protection is that simple.

M cebee

http://www.protekuk.co.uk/surge-guard.pdf

there's a link there

on page 3 it shows one spd for tn-c-s

and 2 spd's for tn-s and tt

lucernarian

I'd assume one spd for tn-c aswell?

euser1984

westom wrote: »

Already answered.

Ok but your post is very technical - there are alot of terms in there that I don't really understand.

M cebee

1 is all you need

assuming you're tn-c-s


if you had the old TT overhead supply you'd need 2

westom

euser1984 wrote: »

Ok but your post is very technical - there are alot of terms in there that I don't really understand.

Then post the sentence and ask for clarification. Nothing in that post is technical. Most everything is what layman are expected to know. You do know what earth ground is and why it was always essential for human safety. You do see how many AC electric wires enter the building. Each wire must have a short (ie 'less than 3 meter') connection to the same earth ground also used by telephone, cable, and satellite dish.

Every utility wire must connect to that earth ground either directly or via a protector. Best surge protection means a wire connects directly to earth ground (where it enters the building). Or the wire makes the same 'short as possible' connection to earth via a protector.

View M cebee's citation from protekuk.co.uk. Figure 3 shows the green and yellow wire. That wire to earth ground must be as short as possible (ie 'less than 3 meters'). Many electricians do not understand that. Every meter longer only compromises protection. If necessary, an electrician should earth that electrode so that the connection to earth is shorter.

His figure shows two wires entering. One (neutral) connects directly to earth. All others must connect to earth via a protector.

I never understand anything new until the third reread. If I understand anything in a first reading, then it was old and already known. Suggest you do same. Because a more than 100 year old and well proven solution is so unknown to most.

This simple: Every single wire connects short (ie 'less than 3 meters') to earth either by a bonding wire or via a 'whole house' protector. Because earth ground (not a protector) does the protection.

lucernarian

I wouldn't say the language is technical, but parts of your posts have strange ways of wording things: you have "earth ground" when earth or ground would normally be used in these sorts of discussions. And "protector"? What about protective conductor? "AC wires"? Neutral and live supplies or conductors are normally referred to separately, and that's central to this thread. Or else it's called the "mains supply". Also, there are some grammatical slips in the posts which I don't like pointing out in threads, I'm just saying that I could see why someone might find your points hard to follow.

westom

To_be_confirmed wrote: »

I wouldn't say the language is technical, but parts of your posts have strange ways of wording things: you have "earth ground" when earth or ground would normally be used in these sorts of discussions.

Motherboard ground is connected to safety ground is connected to chassis ground is connected to a neutral ground is connected to earth ground. All are electrically different. For example, a protector connected to safety ground in a wall receptacle is not earthed. Many grounds exist and are not same. A safety ground (or equipment ground) in a wall receptacle is not earth ground for a long list of reasons.

To surges, all incoming wires are same. Either that wire connects directly and short to earth ground. Or it makes that connection via a protector. Call the wire a neutral, hot, live, AC mains, telephone, signal, antenna, twisted pair, coax, or Ethernet. It must still connect to earth either directly or via a protector. Otherwise building protection is compromised.

Confusing is when all grounds are assumed to be same. They are not. Safety ground, chassis ground, motherboard ground, and earth ground are all interconnected and all electrically different.

Protector and protective conductor are two completely different items.

Does not matter what a wire is called. If a wire enters a building, then it must be earthed directly (the best surge protection) or it must be earthed via a protector. A connection that must be short (ie 'less than 3 meters').

Even a protector and protection are two different items. A protector is only as effective as its protection. Protection is 'single point earth ground'. Yes, all four words have electrically important significance. Every incoming wire must connect to the one, only, and best earth ground. The single point earth ground. Appreciate how new these 100+ year old concepts can be. So yes, rereading will be necessary.

lucernarian

Another poster (M ceebee) had quickly clarified the situation by now. And the answer was dependent on the earthing system used, something which your posts have yet to mention. Where have you mentioned TN-C-S for example? And why in all honesty would you need to point out that "earth" was also a ground?! We're not talking about electronics, but simple electrics stemming from a specific set of circumstances (the incoming low voltage AC supply for a house). The two equate to the same thing in domestic mains supply, it's a principle that TN-C or TN-C-S exploits.

If I took what you were saying about wires literally, it would mean that all mains supply wires should be earthed at point of entry to a premises, including the live! Can you see what I mean about the importance of accurate and relevant wording?

westom

To_be_confirmed wrote: »

And why in all honesty would you need to point out that "earth" was also a ground?

OP's question is about installing a 'whole house' protector. Installed to protect electronics and all other household appliances. Apparently you did not understand why ‘whole house’ protectors are installed.

Any protector is ineffective if connected to any other ground. Earth ground is different from all other grounds. To even to protect the stove and furnace. Apparently you did not know why ‘whole house’ protectors are earthed. Did not even know the difference between earth ground and all other grounds.

OP is asking how to ground every wire. Every incoming wire must be earth grounded either directly or via a ‘whole house’ protector. That answers the OP’s question. Simple to understand if you had learned a difference between earth grounds and all other grounds.

All incoming wires must be earthed either directly or via a 'whole house' protector. M cebee's citation from protekuk.co.uk. Figure 3 shows the green and yellow wire that must connect to earth ground. Not any other ground. Earth ground. That wire to the earthing system must be as short as possible (ie 'less than 3 meters' to earth). Every meter shorter makes a 'whole house' protector even more effective.

Why are you creating confusion with jargon such a T-T or TN-C-S? A solution found all over the world need not know that jargon. Every wire is surge protected when connected directly to earth (best protection) or via a 'whole house' protector. That simple. Repeated at least five times. Why is it confusing? It isn’t.

Bruthal

In a tn-c-s system, one device is connected between Live and the Earth bar, and in reality it could also be connected between Live and neutral bar as the N and E are combined at the meter. But Live and Earth would be the norm. The earth bar will have both the earth rod and the neutral connected to it, so its the best place to connect the surge device.

The items at risk from surges in an installation will have and voltage surge between their Live and neutral, and their live and earth, and since earth and neutral are common in the tn-c-s at the connection point of the installation, there will be no difference between N and E, as they are in reality a low impedence common conductor once the earth protective conductors are all in good order.


In a TT it will be 2 devices, because in a TT system, there can be a surge potential difference between the installation neutral, and its earthing, which means there will be 2 distinct paths back for the surge current. 2 devices will cover this.

So the difference between the tn-c-s and the tt is relevant here.

westom

robbie7730 wrote: »

... since earth and neutral are common in the tn-c-s at the connection point of the installation, there will be no difference between N and E, as they are in reality a low impedence common conductor once the earth protective conductors are all in good order.

They may be low resistance. But the important numbers was short (ie 'less than 3 meters') every meter shorter significantly decreases impedance; increases protection. The distance from each AC (live, neutral, common, or whatever) wire to earth is critically important. Even sharp bends or wire inside metallic conduit in a connection to earth significantly increases impedance. Does not increase impedance for AC (50 cycle) power. But drastically increases impedance to a surge.

Distance from every AC wire to the earthing electrode must be as short and direct as practicable. Protection also increases with more earthing electrodes. Because protection is defined by the quality of and connection to earth ground.

M cebee

the wiring rules also answer this question page 107

GreySquirrel

there is a diagram 53.3 on page 108 of the 4th edition rules. However there is no legend to explain it.

Can someone "translate" please