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Can you show a link of where it says you have to have a TNCS if doing a rewire... First I have every heard of this...Yes. Currently we have no other options
My thinking is that it's more a question of when than "if"
Discuss Mixing TT and TNCS supply systems in the UK Electrical Forum area at ElectriciansForums.net
Can you show a link of where it says you have to have a TNCS if doing a rewire... First I have every heard of this...Yes. Currently we have no other options
My thinking is that it's more a question of when than "if"
We only have a reliable solution if all 3 phases are present
the current signle phase options are not really a solution
I think the DNOs should implement PEN fault disconnection as they have access to all phases easily, but that would require more cost
The DNO (ESB) will only provide you with a TNCS supply. On coming across a TT supply, a REC (registered electrical contractor) is obliged to issue a "Notice of Hazard" to the homeowner, alerting them of the requirement to upgrade to TNCS. No exceptions are allowed.Can you show a link of where it says you have to have a TNCS if doing a rewire... First I have every heard of this...
It's an 80 amp DP isolator.I thought the ROI now mandated double-pole MCB as the main incomer switch,
Correctso I presume the 'neutralising link' is at the supply head, and not in the CU?
The DNO (ESB) will only provide you with a TNCS supply. On coming across a TT supply, a REC (registered electrical contractor) is obliged to issue a "Notice of Hazard" to the homeowner, alerting them of the requirement to upgrade to TNCS. No exceptions are allowed.
On the most recent "Safe Electric" newsletter, they doubled down on this by stating that metal sheds may not be connected to a converted TT supply (see March 2021 newsletter under "faq, s" on page 12, I think).
If there's a main overcurrent protective device upstream in the cabinetIt's an 80 amp DP isolator.
Has the nature of the hazard been described?On coming across a TT supply, a REC (registered electrical contractor) is obliged to issue a "Notice of Hazard" to the homeowner, alerting them of the requirement to upgrade to TNCS. No exceptions are allowed.
The description of the hazard would simply be termed as the home being "un-neutralised".Has the nature of the hazard been described?
Yes. That's one issue. But main issue is the gradual disappearance of the metallic network that was deemed essential for a sustainable TT system.Is it this very issue of TT'd homes returning open PEN current via another's neutralising link?
A protective device that requires a person to receive a shockThese systems only disconnect the supply if the L - N voltage is outside of range of 207v - 253v it is still very possible to have a PEN fault with a dangerous voltage present on all exposed metal work and these devices would be non the wiser, therefore they do not protection against PEN faults in everycase
Other products have a device which senses any current flowing on the CPC, these require a person or animal to receive a shock for a very short duration in order for them to disconnect in a PEN fault scenario
So as yet we do not really have a satisfactory single phase PEN fault detection/protection device
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