**** Pump and MCBs!

[JohnW2]

From the MI, the product of efficiency and power factor is 0.49.

OK - but that's a rather odd quantity ....

At 240V, that gives 13A in fact, so my figure was a bit low, but in the right area.

1500W at 12V240V would equate to a current of 12.76A (near enough to 13A!) with a PF of 0.49, but the "efficiency" would then have to be 100% for the current to be 12.76A if the "product of efficiency and PF" were 0.49. To get 13A with a "product of efficiency and PF" of 0.49 would require the "efficiency" to be about 101.9%.

Kind Regards, John
Edit: Typo Corrected

 

[EFLImpudence]

Typo.

 

[JohnW2]

Typo.

Whose typo (mine?), and where?

Kind Regards, John

 

[EFLImpudence]

1500W at 12V would equate to a current of 12.76A

 

[JohnW2]

Ah - thanks. Now corrected. Not so much a typo as a brain malfunction - even my fingers are unlikely to type "12" when they have been told to type "240"

Kind Regards, John

 

[charliegolf]

Thanks everyone. Have located a 16A MCB on ebay, so hopefully sorted tomorrow. My electrician will be fitting it. But I'd like to ask... is changing this MCB for one with a higher threshold notifiable in Wales? Would a series of tests nomally be carried out after the exchange?
Ta

CG

 

[Simon35]

OK - but that's a rather odd quantity ....
1500W at 12V240V would equate to a current of 12.76A (near enough to 13A!) with a PF of 0.49, but the "efficiency" would then have to be 100% for the current to be 12.76A if the "product of efficiency and PF" were 0.49. To get 13A with a "product of efficiency and PF" of 0.49 would require the "efficiency" to be about 101.9%.

Kind Regards, John
Edit: Typo Corrected

How do you know the power factor of the motor is 0.49?

 

[JohnW2]

How do you know the power factor of the motor is 0.49?

I don't, and on the basis of what I told you, it clearly isn't (unless 'efficiency' is exactly 100%).

What I was saying was that IF the PF were 0.49, then 1500W at 240V would equate to a current of 12.76A (near enough to your 13A) - and I could have added, for clarity, that to get exactly your 13A figure, PF would have to be about 0.48 (more precisely, about 0.4808).

You tell us that the "product of efficiency and PF" is 0.49 and that results in the current being 13A. Since, as above, the get 13A would require a PF of about 0.4808, if the "product of efficiency and PF" were 0.49, that would mean that 'efficiency would (as I wrote before) have to be about 1.019 (0.49 / 0.4808) - i.e. an 'efficiency' of about 101.9%.

Do they explain what they mean by 'efficiency'?

Kind Regards, John

 

[JohnW2]

T...But I'd like to ask... is changing this MCB for one with a higher threshold notifiable in Wales?

Good question, and it really depends upon how one interprets the word "replace". In Wales, "replacing any fixed electrical equipment" is not notifiable provided that it does not involve the provision of new fixed cabling or a new CU. Whether 'replace' includes changing an MCB for one of different rating, I don't know. On the face of it, it would seem a little unlikely that they intended that one could change all the MCBs in a CU to ones of different ratings without notification, but I really don't know.

I'll be interested to hear what others think.

Would a series of tests normally be carried out after the exchange?

Appropriate inspection and testing is required after any electrical work.

Kind Regards, John

 

[securespark]

Good question...I'll be interested to hear what others think.
Appropriate inspection and testing is required after any electrical work.

I was told if the breaker is changed for one of different values, it makes the circuit a "new" circuit and strictly speaking an EIC should be produced just for that circuit.

When I changed the dodgy Wylex breakers, I just did a MWC, with IR & Zs.

 

[JohnW2]

I was told if the breaker is changed for one of different values, it makes the circuit a "new" circuit and strictly speaking an EIC should be produced just for that circuit.

Yes, I would think that a change of OPD rating probably warrants an EIC (and the associated testing), but that is somewhat different from the OP's question about notifiability (in Wales).

One obvious thing about changing the rating of an OPD (particularly an 'upwards' change) is that it involves 'design' decisions, and the impression I get is that the intention in Wales (as previously in England) is that that none of the things allowed without notification really involve any design issues. I therefore remain uncertain about the notifiability (in Wales). Do you have any thoughts?

In England, now, it would presumably not be notifiable. If one changed all the OPD's then that might be getting rather close to 'replacing the CU', but I can't see that changing just one would come into that category.

Kind Regards, John

 

[securespark]

I may not have answered that question, but TBF, I was responding to your "I'll be interested to hear what others think."

 

[JohnW2]

I may not have answered that question, but TBF, I was responding to your "I'll be interested to hear what others think."

Fair enough, but I think it was fairly clear that my comment "I'll be interested to hear what others think." related to the OP's question about notifiability (in Wales) - particularly given that it followed immediately after my "...I don't know" and "...I really don't know" in relation to the notifiability question!

Kind Regards, John

 

[EFLImpudence]

Schedule 4 which still applies in Wales is a list of the things which are NOT notifiable.
http://www.legislation.gov.uk/uksi/2010/2214/schedule/4/made

I would think it should be notifiable as it could make the installation less safe and non-compliant if testing is not possible because of lack of knowledge or equipment.

However, it must surely come under - or rather NOT come under and hence NOT be notifiable - the following:

then there is (c)

but you are not refixing or replacing enclosures - or are you?


It's not supposed to make sense.

 

[JohnW2]

Schedule 4 which still applies in Wales is a list of the things which are NOT notifiable.

Indeed so.

I would think it should be notifiable as it could make the installation less safe and non-compliant if testing is not possible because of lack of knowledge or equipment.

1 agree, but ...

However, it must surely come under - or rather NOT come under and hence NOT be notifiable - the following:...

That's what I referred to - but, as I said, it really depends upon the (undefined) meaning of "replace". As above, I agree with you that one would have thought 'replacing' an OPD with one of higher rating 'should' be notifiable. As I also said, I do start wondering when I think about the fact that, using your argument, one could theoretically change all the OPDs in a CU for ones of different ratings without notification - and I find it hard to believe that whoever wrote it intended that such would not be notifiable...

... so, if changing multiple OPDs for ones of different ratings were (should be) notifiable, that might also apply to changing the rating of just one.

Yet again, a problem of absent definitions. I know we all scorn mention of 'like for like replacement' (since the rules don't mention that anywhere) - but this is one situation in which it would be nice to know whether or not they regard changing an OPD for one of different rating as being just a 'replacement'.

Kind Regards, John