Main RDS tripping with lightning

[ericmark]

Two items spring to mind first is the X-Pole which is claimed to resist spikes [url] and the other is

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• ericmark
• 6 Dec 2008
• 34

these I am told cost around £350 each and test the line then auto reset.

However both are expensive and I would just swap for a new S type RCD at 300 ma and see if that improves matters.

For a TT supply 300ma is the size required to protect from fire and S type has a delay. It is permitted to have a socket marked up for freezer only without RCD protection but that refers to the 30ma RCD used for sockets and cables buried at less than 50mm not the main incoming one where it is not a TN earth.

 

[securespark]

the Latin for earth is the same

Trying too hard to look for a quip....

 

[JohnW2]

It is permitted to have a socket marked up for freezer only without RCD protection but that refers to the 30ma RCD used for sockets and cables buried at less than 50mm not the main incoming one where it is not a TN earth.

I think that some might find that statement a bit confusing. Are you saying, as I did, that if it is a TT installation (i.e. 'not TN') then one cannot avoid the requirement for RCD protection (100mA, or maybe 300mA), even for a dedicated (and 'labelled') freezer circuit?

Kind Regards, John

 

[aytonboy]

Just for info. the one main RCD is
a grey box:
Wylex "Residual Current Operated Circuit Breaker"
240V 50HZ 63A Load
WSEM 63/2 100mA Trip

Just in case that makes any difference.

The house has 2 overhead lines bringing in the power. Does that mean we have to have our own earth pin somewhere (TT). I cannot find one outside. Perhaps it could be behind the panel to earth within the cavity wall? Where are these pins usually hidden?

With overhead lines, is TT earthing the only option or can National Grid or our supplier do one of the other sorts of earthing for us?

Useful to know my options before getting an experienced electrician in.

 

[DetlefSchmitz]

... TT supplies (or should that be EE supplies? ) ...

I think the Latin for earth is the same in French as it is in English.

as an aside...

I've wondered for a long time how they would designate these supply types on Lunar Base. But I keep getting bogged down by the (likely) high resistance of the moon's surface, and the effect this would have on distribution.

 

[JohnW2]

The house has 2 overhead lines bringing in the power. Does that mean we have to have our own earth pin somewhere (TT). I cannot find one outside. Perhaps it could be behind the panel to earth within the cavity wall? Where are these pins usually hidden? ... With overhead lines, is TT earthing the only option or can National Grid or our supplier do one of the other sorts of earthing for us? ... Useful to know my options before getting an experienced electrician in.

The fact that you have an overhead supply does not necessarily mean that TT earthing is the only option available. However, the fact that you have a 100mA RCD strongly suggests that you either currently have, or have had in the past, a TT system. The TT electrode (rod/spike), if you have one, would normally be just outside your house.

Is there any chance that you could provide a photo of the supplier's 'service head' (where the supply company's fuse is)?

Kind Regards, John

 

[JohnW2]

I've wondered for a long time how they would designate these supply types on Lunar Base. But I keep getting bogged down by the (likely) high resistance of the moon's surface, and the effect this would have on distribution.

I haven't a clue as to what the resistivity of the moon might be but, if it were very high (seemingly likely, in the absence of water), then I would think that there would be little point in 'earthing' (or 'mooning', or 'luning' ) electricity supplies at all.

Kind Regards, John

 

[aytonboy]

"Suppliers service head"
Is that likely to be where the cable enters the wall just under the roof or back along the two lines at the local reducing transformer. (bit dark at the moment)

 

[JohnW2]

"Suppliers service head"
Is that likely to be where the cable enters the wall just under the roof or back along the two lines at the local reducing transformer. (bit dark at the moment)

It should be fairly close to your meter, connected to the meter by a couple of thick cables. It may be a single entity, but might just be a couple of little 'black boxes' If you follow the cables from your meter and photograph whatever they are connected to (on the supplier's side, not 'your' side), that should do it!

Kind Regards, John

 

[aytonboy]

[GALLERY=media, 68573][/GALLERY]
[img]rl=http://[uwww.diynot.com/network/aytonboy/albums/18292/68574][img]http://media.diynot.com/211000_210582_68574_94380218_thumb.jpg[/url]

 

[aytonboy]

That task was interesting! The pic of the two cables entering under the roof was made "private" somehow or other. This pic is inside the meter box on an external wall. IN and OUT cables run inside the cavity wall. Does seeing the black thing beneath the meter help?

Thanks for your interest JohnW2!

 

[aytonboy]

[GALLERY=media, 68577][/GALLERY]











The other pic

 

[JohnW2]

That task was interesting! The pic of the two cables entering under the roof was made "private" somehow or other. This pic is inside the meter box on an external wall. IN and OUT cables run inside the cavity wall. Does seeing the black thing beneath the meter help?Thanks for your interest JohnW2!

The pic of the 'black thing' (the 'service head' or 'cutout') might well help if we could zoom into it. Could you possibly find a way of posting it in the same way as you did with the other (outdoor) photo (second attempt!) - because that is 'zoomable'?

Kind Regards, John

 

[aytonboy]

View media item 68595




The black box beneath the meter. The digital meter was new in 2010. No sign of an earth cable in the meter box.
Wording on the black box is ISCO Series 3.
Cables beneath the meter are all labelled either L1 or N.

 

[JohnW2]

The black box beneath the meter. The digital meter was new in 2010. No sign of an earth cable in the meter box.
Wording on the black box is ISCO Series 3. Cables beneath the meter are all labelled either L1 or N.

That's certainly not TN (TN-S or TN-C-S), so your supply must be intended to be TT. Whether you actually have a TT rod, or have the (dangerous) situation of not having an earth at all is another question!

Are there any green/yellow insulated cables in the vicinity of your consumer unit and, if so, can you see where they go? Photos might again be helpful.

Kind Regards, John