Posted by: @jamespa

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Posted by: @batpred

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Probably since, as you stated, a leak to earth would impact the reading on the neutral. 

If you have a leak to earth you have a problem which would trip an RCD if the circuit has one.  It's a fault condition.  

Yes, but many circuits do not have RCD/RCBO. As they are not mandatory in all circuits (and as usual the regulations do not mandate them retrospectively...)

Anyway, agree that the clamp should also work around the neutral. 

Another thing I realised is that, when having multiple clamps along the same wire, it is a good idea to have a few cm in between them.

Posted by: @batpred

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Yes, but many circuits do not have RCD/RCBO. As they are not mandatory in all circuits (and as usual the regulations do not mandate them retrospectively...)

True.  But a minor earth leakage will make no significant difference to the measurement and a major one is probably a near short so major enough to blow a fuse/MCB.  There may be a mechanism for an earth leakage that is material but not sufficient to blow a fuse, but it's difficult to think what it is (other than a miswire of course!)

@jamespa 

Makes sense to me. The simpler it is to install it, the more people will do like Mars and not be held back by an electrician visit… 

On a related point, one of my ashp quotes listed the need for an “mcs electrical meter” (assume it is just a ct clamp). I told them i do not need it, but they stated it is mandatory.  I remember some folk posting here and wanting to know how much their heatpump was consuming? Unless they had an mcs meter they would not trust, is it the case of some old rule that no longer applies?

Posted by: @batpred

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@jamespa 

On a related point, one of my ashp quotes listed the need for an “mcs electrical meter” (assume it is just a ct clamp). I told them i do not need it, but they stated it is mandatory.  I remember some folk posting here and wanting to know how much their heatpump was consuming? Unless they had an mcs meter they would not trust, is it the case of some old rule that no longer applies?

Bow Locks.  Ask them to tell you the reference number of the regulation specifies this, the rules are all in the public domain.  Or look elsewhere!  If you are claiming RHI then it may be mandatory, but not otherwise.

Posted by: @jamespa

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Posted by: @batpred

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@jamespa 

On a related point, one of my ashp quotes listed the need for an “mcs electrical meter” (assume it is just a ct clamp). I told them i do not need it, but they stated it is mandatory.  I remember some folk posting here and wanting to know how much their heatpump was consuming? Unless they had an mcs meter they would not trust, is it the case of some old rule that no longer applies?

Bow Locks.  Ask them to tell you the reference number of the regulation specifies this, the rules are all in the public domain.  Or look elsewhere!  If you are claiming RHI then it may be mandatory, but not otherwise.

Very much agree. Even with RHI (and we were one of the last to get in under this scheme), it's only necessary in some cases. We, for instance, do not need any kind of metering to get our repayments.

Bear in mind, of course, that you (either out of your own pocket or via the subsidy scheme you are unlocking) have to pay for every piece of kit that's installed. If it doesn't provide you with a benefit of some kind, why should you pay for it and why should you allow it in your home? If the installer is wanting to put something in that's only for their own benefit, they should be the ones paying for it and even then only installing it with your permission.

Posted by: @majordennisbloodnok

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Very much agree. Even with RHI (and we were one of the last to get in under this scheme), it's only necessary in some cases. We, for instance, do not need any kind of metering to get our repayments.

Bear in mind, of course, that you (either out of your own pocket or via the subsidy scheme you are unlocking) have to pay for every piece of kit that's installed. If it doesn't provide you with a benefit of some kind, why should you pay for it and why should you allow it in your home? If the installer is wanting to put something in that's only for their own benefit, they should be the ones paying for it and even then only installing it with your permission.

Yes, and these guys would probably be my preferred installers, a nice family business. They are however sticking to old habits.

The other thing is he included the buffer tank even when I explicitly excluded it. Now he removed it but claim that the use of a third party tank instead of Vaillant adds to their costs! Having a single line item for 16k was suspicious but they still managed to undermine themselves further. 

A shame, as I will be posting locally when more local folk really start to switch. I will only be able to comment on the old tech and pricing habits.. Like paying for something I do not need and still paying for it when I am not having it. 

At this stage, not even worth the £250 survey.  

Posted by: @jamespa

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Posted by: @batpred

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Yes, but many circuits do not have RCD/RCBO. As they are not mandatory in all circuits (and as usual the regulations do not mandate them retrospectively...)

True.  But a minor earth leakage will make no significant difference to the measurement and a major one is probably a near short so major enough to blow a fuse/MCB.  There may be a mechanism for an earth leakage that is material but not sufficient to blow a fuse, but it's difficult to think what it is (other than a miswire of course!)

An earth fault on a TT derived supply (typically but not exclusively overhead lines) will often not trip an MCB/Fuse (or at least not disconnect the fault within the required time) due to the high EFLI.

In these cases you'd typically use an upfront RCCB for fault protection with the fuses / MCBs providing the overload and short circuit protection. Or more recently every circuit on an RCBO with tail clamps on the main switch. 

Posted by: @ga3_usr

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Posted by: @jamespa

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Posted by: @batpred

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Yes, but many circuits do not have RCD/RCBO. As they are not mandatory in all circuits (and as usual the regulations do not mandate them retrospectively...)

True.  But a minor earth leakage will make no significant difference to the measurement and a major one is probably a near short so major enough to blow a fuse/MCB.  There may be a mechanism for an earth leakage that is material but not sufficient to blow a fuse, but it's difficult to think what it is (other than a miswire of course!)

An earth fault on a TT derived supply (typically but not exclusively overhead lines) will often not trip an MCB/Fuse (or at least not disconnect the fault within the required time) due to the high EFLI.

In these cases you'd typically use an upfront RCCB for fault protection with the fuses / MCBs providing the overload and short circuit protection. Or more recently every circuit on an RCBO with tail clamps on the main switch. 

That was my understanding also.