hot water tap on ring

[mo2]

why on earth do you think im lying? for a laugh!? I'm really not that sad

The work needs to be done, and having realised it can't go on the ring as pnly FCUs and sockets can go on the ring and the power draw is more than 13A, I was asking how I would work out the MCB aize/type and cable size. Simple as. Now I realise this is not something I can do, I will reconsider as I said. But time is running out as the walls are being plasterboarded

 

[mo2]

well i'll be running the cable for sure, and I can do basic bits and pieces, but if someone were to explain what I need to consider in this new situation which I am not familiar with, I would most definitely go and figure the rest out for myself and do it it safely

since none of the Part P police have shown up it's up to me I guess..

you must notify the LABC ( and pay a fee ) in advance of commencing any electrical work in a kitchen, bathroom, shower room, outdoors and for any work involving the provision of new fixed cabling, a new circuit, and altering of the OCPD.

you can use a registered electrician who will do the notifying for you, or as above, DIY and pay the fee..

as this is titled "Hot water tap" then it's a safe bet that it's for work in a kitchen or bathroom...

look up part P in the wiki at the top of the page.

for your circuit you want 2.5mm² cable and a 16A B type breaker, a 20A DP switch

wow your last line, missed that thanks

And yeah, it's not a kitchen/bathroom but ofc there are new ccts. I have already breached part p a few times in the house, and I'll worry about that in the very very distant future when it comes to selling. Perhaps foolish, I know, but that's what we've done/are doing.

EDit: Also the connection to the CU comes later so I may look at getting/borrowing whatever is needed to do the testing or even ask a spark who would happy not seeing the cable run ( )

 

[ban-all-sheds]

why on earth do you think im lying? for a laugh!? I'm really not that sad

Oh I'm sure you prefer the term "wind up".

And in a "wind up" you say things which are not true to see what reaction you get - either for pathetic amusement or because you're one of those w*****s who thinks he's on a mission to expose dangerous advice given to people who patently don't have a clue.

Saying things which are not true and intending that they should be believed is lying.

 

[mo2]

my point is Mr. BAS that that is not what I am doing.

I had a genuine problem and have now understood what needs to be done. I have bought the handwash unit and I have also already put in the cable. I actually used 4mm even though im using a 3kw unit to be sure.

I think I'll unsubscribe from this topic

 

[ColJack]

you work fast.. 12pm and you only just got the info you needed, 1:57pm and you've been to the shops, bought the cable and installed it..

 

[comms]

Flippin heck bas you used to be so easy going..............bumped your noggin or what

Have to agree though some posts of late (here & other forums) do seem to be posted by either;

(1) those at college/on courses, who know a little bit of knowledge but are asking for clarification on a question & dont want to be shot down so give it the old "I'm doing some diy" banter

(2) Out & out lets sound like a numpty & see if we get some carp advise from a sperks

(3) are a member of another forum & have seen a question/ post on the other forum, but then visit elsewhere (here or another forum of your choice) asking the same question get advice so they can return to original forum & post an answer

(4) just think it's fun to get a bite by asking loon questions

(5) are genuinely thick as Scheiße & are a danger to themselves & should be kept clear of all sharp implements & electrical wiring.

 

[holmslaw]

Flippin heck bas you used to be so easy going..............

When was that then?

 

[comms]

Flippin heck bas you used to be so easy going..............

When was that then?

A long long very long so long ago .........no infact I think I must have been mistaken

 

[ban-all-sheds]

Flippin heck bas you used to be so easy going..............bumped your noggin or what

Have to agree though some posts of late (here & other forums) do seem to be posted by either;

(1) those at college/on courses, who know a little bit of knowledge but are asking for clarification on a question & dont want to be shot down so give it the old "I'm doing some diy" banter

(2) Out & out lets sound like a numpty & see if we get some carp advise from a sperks

(3) are a member of another forum & have seen a question/ post on the other forum, but then visit elsewhere (here or another forum of your choice) asking the same question get advice so they can return to original forum & post an answer

(4) just think it's fun to get a bite by asking loon questions

(5) are genuinely thick as Scheiße & are a danger to themselves & should be kept clear of all sharp implements & electrical wiring.

So let's see.

We have somebody who uses the term "ring final".

He knows that the characteristics of radials are different, and voltage drop, current carrying capacity calculations are not the same.

He knows that Type B is a significant feature of an MCB.

He then throws in that he is thinking of possibly using a 20A FCU, and writes both "3kw will blow the 13A fuse" and "wouldn't the 3kw be less than 13A".

And he tries to jolly it all up with phrases like "A 3kw water heater thingee mabobbee" and "with the FCU it'd be 4 points if ya know what I mean".

I'm convinced he's (2) and/or (4), and let's not put a gloss on it all - if he's writing untrue things hoping that they will be believed he is a liar.

 

[securespark]

[Ding Ding]

"Round Three!"

 

[Chri5]

BAS I genuinely appreciate your learned muses, but of late you have become tetchy, rude and this does you a disservice.

There's no need to slip down towards the gutter with rude and inflammatory remarks. If you don't like the OP, think they are being snide or attempting wind up's- would it not be easier to ignore the post and simply not make comment ?

Sometimes people say more by not saying anything.

More and more frequently you do seem to be raising peoples neck hairs, more and more posts descend in to negativity- surely this could all be avoided by keeping the comments going without the use of negative remarks and personal thoughts ?

Give advice, but please try not to insult or offend- It simply makes your on line persona look like a c0ck, and that's not who you are.

On good days your learned, considered responses are an asset to you and this forum- Lets have more good days !

 

[ericmark]

At least Mo2 is trying to do things right and has actually asked about volt drop and even if he can’t understand at least we can tell him so here goes.

The volt drop permitted is 5% within the premises on a ring main this will give one 106 meters of 2.5mm cable on a 32A supply.

This is worked out by first taking the volt drop of the cable which is 18mV/A/m this value then needs correcting there is a complex formula which takes into account the voltage v = 230
max temp ta = 70
rating factor for ambient temp Ca = 1
rating factor for group Cg = 1
design current of circuit lb = 26 (see note)
Tabulated current carrying capacity of cable It = 40 which gives us the factor for operating temp of conductor Ct = 0.923 using details given. This x the original 18mV/A/m gives true volt drop
Note:- for standard ring main it is considered that 20A is drawn at centre point and the remaining 12 even spread throughout length so is halved giving 6A so total is 26A not 32A for calculation this assumes no more than 2Kw per fixed appliance.
When connecting fixed appliances over 2Kw then these figures will not be true.
I use excel to work out figures and I have not got BS 7671 to hand to give you formula.

This also assumes you have a RCD to protect against Line – Earth faults. If your not using an RCD then the cable if buried in wall or ceiling at less than 50mm will need to comply with one of a list of BS numbers which does not include twin and earth but does include Ali-tube cable to BS 8436 Guardian, Earthshield, Flexishield, or Afumex.

Also you will need to measure Line and Earth loops or R1 + R2 depending or if ring or radial or use an earth loop impedance tester to measure direct. If you are using an RCD then you will need to measure tripping time with an RCD tester.

The earth loop impedance is dependent on the protective device use for example a 32A MCB code B needs 5 x 32A to trip on magnet part so needs 160A to trip within time allowed 230v/160A = 1.4375 Ohms and the earth loop impedance needs to be less than this Table 41.3 in BS 7671 gives you these values with out needing to calculate and gives 1.44 ohms as rounded value. See page 49.

A 13A fuse has value of 2.42 ohms.

To be able to safely complete most wiring alterations you will need to test and this normally needs three meters.

1) Ohm meter which on high ohm range uses 500v and on low ohms range uses min of 200ma I think?

2) Earth loop impedance meter which will normally also measure prospective short circuit current.

3) RCD meter which tests not only at what leakage it does and does not trip but also the time it takes.

All these meters cost around £250 each there are combined meters which will do all and often refers to as 16th Edition test sets now 17th Edition.
It is near impossible for the DIY person to comply with the requirements.

There will be Electricians who would normally work on commercial equipment who are not Part P registered but have the skills and equipment to do the work so for them they can take the LABC inspection route.

It is up to the LABC to allow or dis-allow you to do the work and if they feel you lack the skill they can refuse to allow you to do the work.
The rules on ring and radial supplies using 13A outlets were corrected so are available for down load at
http://www.theiet.org/publishing/wiring-regulations/updates/ see BS 7671:2008, Corrigendum (July 2008)

OK no funny faces or derogatory remarks but are you really any the wiser?

 

[ban-all-sheds]

I'm not trying to insult or offend, at least not in a negative or destructive way.

If I express the contempt that I feel for liars or racists for example then I regard that as a positive and constructive thing to do. I absolutely believe in what Edmund Burke said, and I believe that your position of if I believe that someone is being snide or lying to take the easy way out and just say nothing is wrong and shameful.