As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD.
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD.
I think I'll stick with
Morcambe and Wise before bed next time!
Scott <newsgroups@gefion.myzen.co.uk> wrote:
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take
anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
Have a look at your incoming cable. If it has the earth wired to the sheath of the cable that's TNS. If the earth goes into the neutral terminal that's TNCS (or a PME sticker). If you have an outdoor earth rod that's TT.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be 200 ohms
- the fault current wouldn't trip an MCB but it would trip an RCD. If next door causes your earth to go live via the water pipe, your RCD won't help
but your earth bonding should shunt much of the current to your real earth. On TT your neighbour should have an RCD that trips.
On 23/12/2024 13:22, Theo wrote:
Scott <newsgroups@gefion.myzen.co.uk> wrote:
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take
anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
Have a look at your incoming cable. If it has the earth wired to the sheath >> of the cable that's TNS. If the earth goes into the neutral terminal that's >> TNCS (or a PME sticker). If you have an outdoor earth rod that's TT.
Note that an earth rod can also be added to a TN-C-S install - it just >becomes another of the Multiple earths of PME.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be 200 ohms >> - the fault current wouldn't trip an MCB but it would trip an RCD. If next >> door causes your earth to go live via the water pipe, your RCD won't help
but your earth bonding should shunt much of the current to your real earth. >> On TT your neighbour should have an RCD that trips.
If the neighbour has a disconnected neutral, but there is a path to your >neutral via theirs and yours equipotential bonding, then their RCD may
not see a fault since there will be a balance between live and what it
is seeing as neutral.
On Mon, 23 Dec 2024 16:16:14 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 13:22, Theo wrote:
Scott <newsgroups@gefion.myzen.co.uk> wrote:
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take >>>> anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
Have a look at your incoming cable. If it has the earth wired to the sheath >>> of the cable that's TNS. If the earth goes into the neutral terminal that's >>> TNCS (or a PME sticker). If you have an outdoor earth rod that's TT.
Note that an earth rod can also be added to a TN-C-S install - it just
becomes another of the Multiple earths of PME.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be 200 ohms >>> - the fault current wouldn't trip an MCB but it would trip an RCD. If next >>> door causes your earth to go live via the water pipe, your RCD won't help >>> but your earth bonding should shunt much of the current to your real earth. >>> On TT your neighbour should have an RCD that trips.
If the neighbour has a disconnected neutral, but there is a path to your
neutral via theirs and yours equipotential bonding, then their RCD may
not see a fault since there will be a balance between live and what it
is seeing as neutral.
Would it not be safer to have an isolated section on the incoming
water pipe?
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take >anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
On 23/12/2024 12:56, Scott wrote:
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take
anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
Details of the types and how to tell which you have here:
https://wiki.diyfaq.org.uk/index.php/Earthing_Types
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD.
Indeed...
However (most) RCDs have no earth connection, so if it is the earth
which is introducing a potential into your house, the RCD won't see it,
and even if it tripped, it would not disconnect the earth.
(which is why we have equipotential bonding)
I think I'll stick with
Morcambe and Wise before bed next time!
Bring me sunshine :-)
John.. Do any RCD's have an earth connection i thought it was only the
very old e-RCD was it called?..
However (most) RCDs have no earth connection, so if it is the earth
which is introducing a potential into your house, the RCD won't see it,
and even if it tripped, it would not disconnect the earth.
John.. Do any RCD's have an earth connection i thought it was only the
very old e-RCD was it called?..
On 23/12/2024 17:00, Scott wrote:
On Mon, 23 Dec 2024 16:16:14 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 13:22, Theo wrote:
Scott <newsgroups@gefion.myzen.co.uk> wrote:
As a distraction from all the Christmas stuff, I watched John Ward's >>>>> YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take >>>>> anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next >>>>> door's wiring.
Have a look at your incoming cable. If it has the earth wired to the sheath
of the cable that's TNS. If the earth goes into the neutral terminal that's
TNCS (or a PME sticker). If you have an outdoor earth rod that's TT.
Note that an earth rod can also be added to a TN-C-S install - it just
becomes another of the Multiple earths of PME.
What about an RCD? I thought the RCD/RCBO measured any difference in >>>>> current between the 'brown' and the 'blue' and therefore any leakage >>>>> to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be 200 ohms
- the fault current wouldn't trip an MCB but it would trip an RCD. If next
door causes your earth to go live via the water pipe, your RCD won't help >>>> but your earth bonding should shunt much of the current to your real earth.
On TT your neighbour should have an RCD that trips.
If the neighbour has a disconnected neutral, but there is a path to your >>> neutral via theirs and yours equipotential bonding, then their RCD may
not see a fault since there will be a balance between live and what it
is seeing as neutral.
Would it not be safer to have an isolated section on the incoming
water pipe?
Possibly, but were do you stop? Gas pipe, oil pipe, building metalwork,
that TT earth on an outbuilding submain etc. It is difficult to make
sure you catch all possible connections to an unintended earth.
In article <vkc21n$199f6$2@dont-email.me>, John Rumm <see.my.signature@n owhere.null> scribeth thus
On 23/12/2024 12:56, Scott wrote:
As a distraction from all the Christmas stuff, I watched John Ward's
YouTube video on diverted neutral current last night. I just about
followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find
out which system I have, bearing in mind John's admonition not to take
anything apart. It is quite alarming to think I could encounter 230
volts in my tap next time I take a shower because of a fault in next
door's wiring.
Details of the types and how to tell which you have here:
https://wiki.diyfaq.org.uk/index.php/Earthing_Types
What about an RCD? I thought the RCD/RCBO measured any difference in
current between the 'brown' and the 'blue' and therefore any leakage
to earth would immediately trip the RCD.
Indeed...
However (most) RCDs have no earth connection, so if it is the earth
which is introducing a potential into your house, the RCD won't see it,
and even if it tripped, it would not disconnect the earth.
John.. Do any RCD's have an earth connection i thought it was only the
very old e-RCD was it called?..
tony sayer <tony@bancom.co.uk> wrote:
ELCB - Earth Leakage Circuit BreakerHowever (most) RCDs have no earth connection, so if it is the earth
which is introducing a potential into your house, the RCD won't see it,
and even if it tripped, it would not disconnect the earth.
John.. Do any RCD's have an earth connection i thought it was only the
very old e-RCD was it called?..
On Mon, 23 Dec 2024 21:43:58 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 17:00, Scott wrote:
On Mon, 23 Dec 2024 16:16:14 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 13:22, Theo wrote:
Scott <newsgroups@gefion.myzen.co.uk> wrote:
As a distraction from all the Christmas stuff, I watched John Ward's >>>>>> YouTube video on diverted neutral current last night. I just about >>>>>> followed the explanation about the three earthing systems (TN-S,
TN-C-S and TT). I am now wondering if there is an easy way to find >>>>>> out which system I have, bearing in mind John's admonition not to take >>>>>> anything apart. It is quite alarming to think I could encounter 230 >>>>>> volts in my tap next time I take a shower because of a fault in next >>>>>> door's wiring.
Have a look at your incoming cable. If it has the earth wired to the sheath
of the cable that's TNS. If the earth goes into the neutral terminal that's
TNCS (or a PME sticker). If you have an outdoor earth rod that's TT.
Note that an earth rod can also be added to a TN-C-S install - it just >>>> becomes another of the Multiple earths of PME.
What about an RCD? I thought the RCD/RCBO measured any difference in >>>>>> current between the 'brown' and the 'blue' and therefore any leakage >>>>>> to earth would immediately trip the RCD. I think I'll stick with
Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be 200 ohms
- the fault current wouldn't trip an MCB but it would trip an RCD. If next
door causes your earth to go live via the water pipe, your RCD won't help >>>>> but your earth bonding should shunt much of the current to your real earth.
On TT your neighbour should have an RCD that trips.
If the neighbour has a disconnected neutral, but there is a path to your >>>> neutral via theirs and yours equipotential bonding, then their RCD may >>>> not see a fault since there will be a balance between live and what it >>>> is seeing as neutral.
Would it not be safer to have an isolated section on the incoming
water pipe?
Possibly, but were do you stop? Gas pipe, oil pipe, building metalwork,
that TT earth on an outbuilding submain etc. It is difficult to make
sure you catch all possible connections to an unintended earth.
I regret to say that in the seasonal spirit of Christmas I watched
another 'JW' YouTube video last night and he actually said the best
way to install a TT system for an existing property is to use a
plastic water pipe. I think he also said that a plastic gas pipe can
be used outdoors but not indoors.
On 24/12/2024 09:58, Scott wrote:
On Mon, 23 Dec 2024 21:43:58 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 17:00, Scott wrote:
On Mon, 23 Dec 2024 16:16:14 +0000, John Rumm
<see.my.signature@nowhere.null> wrote:
On 23/12/2024 13:22, Theo wrote:
Scott <newsgroups@gefion.myzen.co.uk> wrote:Note that an earth rod can also be added to a TN-C-S install - it just >>>>> becomes another of the Multiple earths of PME.
As a distraction from all the Christmas stuff, I watched John Ward's >>>>>>> YouTube video on diverted neutral current last night. I just about >>>>>>> followed the explanation about the three earthing systems (TN-S, >>>>>>> TN-C-S and TT). I am now wondering if there is an easy way to find >>>>>>> out which system I have, bearing in mind John's admonition not to >>>>>>> take
anything apart. It is quite alarming to think I could encounter 230 >>>>>>> volts in my tap next time I take a shower because of a fault in next >>>>>>> door's wiring.
Have a look at your incoming cable. If it has the earth wired to
the sheath
of the cable that's TNS. If the earth goes into the neutral
terminal that's
TNCS (or a PME sticker). If you have an outdoor earth rod that's TT. >>>>>
What about an RCD? I thought the RCD/RCBO measured any difference in >>>>>>> current between the 'brown' and the 'blue' and therefore any leakage >>>>>>> to earth would immediately trip the RCD. I think I'll stick with >>>>>>> Morcambe and Wise before bed next time!
Yes. Particularly required on TT where the earth impedance can be >>>>>> 200 ohms
- the fault current wouldn't trip an MCB but it would trip an
RCD. If next
door causes your earth to go live via the water pipe, your RCD
won't help
but your earth bonding should shunt much of the current to your
real earth.
On TT your neighbour should have an RCD that trips.
If the neighbour has a disconnected neutral, but there is a path to
your
neutral via theirs and yours equipotential bonding, then their RCD may >>>>> not see a fault since there will be a balance between live and what it >>>>> is seeing as neutral.
Would it not be safer to have an isolated section on the incoming
water pipe?
Possibly, but were do you stop? Gas pipe, oil pipe, building metalwork,
that TT earth on an outbuilding submain etc. It is difficult to make
sure you catch all possible connections to an unintended earth.
I regret to say that in the seasonal spirit of Christmas I watched
another 'JW' YouTube video last night and he actually said the best
way to install a TT system for an existing property is to use a
plastic water pipe. I think he also said that a plastic gas pipe can
be used outdoors but not indoors.
Yup plastic gas pipes outside are common in the distribution system, and often right up to a premises these days, but less so after the meter on
the consumer side. Trackpipe (plastic coated corrugated steel) is quite common though.
John Rumm wrote:
plastic gas pipes outside are common in the distribution system,
and often right up to a premises these days,
Up to the premises, but *never* inside the boundary of a building
including uninhabited spaces like garages.
I think he also said that a plastic gas pipe can
be used outdoors but not indoors.
On 24/12/2024 09:58, Scott wrote:
I think he also said that a plastic gas pipe can be used outdoors but
not indoors.
Gas regulations! Plastic buried underground, is much less likely to be
melted by the heat from a fire, and less of an issue, even it it did. A plastic gas pipe subjected to heat in a building, would be much more
serious.
Harry Bloomfield Esq <harry.m1byt@outlook.com> wrote:
On 24/12/2024 09:58, Scott wrote:
I think he also said that a plastic gas pipe can be used outdoors but
not indoors.
Gas regulations! Plastic buried underground, is much less likely to be melted by the heat from a fire, and less of an issue, even it it did. A plastic gas pipe subjected to heat in a building, would be much more serious.
My house was built in the 70s, water pipe is plastic. Gas pipe appears as plastic coated steel. I have a substantial earthing system connected from my amateur radio aerials (10mm^2 and at least 10 earth roda and many buried wires). I'd like to convert to a TT system, but if I disconnect my supplied earth and check the earth loop impedence to my system it is about 6 ohms. Is this likely to be the earth bonding to the gas pipe (Unable to disconnect easily due multiple paths through boiler etc) to the earth next door. If so can I get teh gas people to fit an isolating section in the pipe?
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