60amp supply 100amp consumer unit

[firedrew]

Hi all, im recently qualified so please be gentle! we all have to start somewhere

I am looking at a possible rewire for an old property that has a 60 amp supply i can keep the maximum demand down to 60 amp but all the consumer units available have a 100 amp isolator. is ok to use this with a 60 amp supply?

 

[Sharpend]

In a nutshell the 100amp isolator is capable of operating to 100amp doesn't mean that it has too, so less than the 100 will be fine.

Welcome!

 

[firedrew]

Thanks alot! i thought as much just looking for confirmation. and thanks for a straight answer i have looked at this site alot and seen the experienced guys jump on the newbies so was a bit unsure you have restored my faith!

 

[paul b b]

On another note...don't forget to take discrimination into account when you do your circuit design

 

[steptoe]

Firedew, that only usually happens when someone comes on pretending to be something they are not, and asking questions that they really should know the answer to, ie, basic 1st year stuff.

 

[moose man]

hi and welcome to the forum

you could ask the dno to upgrade cut out to 80A but this will be the max they would do free of charge as norm its only 16mm supplying

cut out on there side just in case anything is added in the future i had the same issue on my own propperty and the yreplaced and upgraded

the cut out for no charged

 

[firedrew]

Thanks for all you advice

i spoke to them yesterday and they wanted

 

[Evans Electric]

And don't forget , Firedrew , that a HRC fuse will happily carry currents equal to and above (for a period ) and also sudden surges without blowing .

 

[SLIPSHOD & SLAPDASH]

I saw a similar job to this and the tail magically grew to 25mm overnight. Saved me some grief.

 

[adammid]

Welcome. I did a job in an ex council house. It had a 50amp HRC fuse. When council properties were built many moons ago the dno installed the smallest fuse they could get away with but the tails were still o16mm2. The main fuse blew, could have been a coincidence but I put it down to the property being empty for a while and no power used to suddenly being on all the time, builders plugging everything in etc and the dno came and swapped the fuse over and put a 80amp fuse in, free of charge. A 60amp HRC fuse would prob take about 80amps before it popped.

 

[MSH1601]

I should ask to see their price list!! We had them called out to assess (foc). Told us it would be

 

[apprentice87]

Hi Firedrew,

To be honest, i would forget all about the size of the fuse in the cutout. It is unlikely that you will EVER blow it no matter what you do.....

Have a look at the curves for a BS1361 fuse and see just how much current it takes to blow one...

Years ago i had a single phase welder here. I used it for about 20 years at least. Not long ago, out of interest, i put a clamp meter on the feed to it....109 amps.......

With diversity, i think you can safely forget all about the fuse...

john...

 

[M107]

Tell dno the cutout is getting hot & you've isolated for safety...........bet they come out and change & upgrade it foc.

 

[Electroglow]

I have an apprentice that manged to blow his main fuse at his house. 2nd year, he tryed to change his mums c. As he was trying to take the earths out (still live) he bridged the I coming l and n and blew my brand new nip ex long nose pliers. Not a happy man.

I then went there in the morning and gave him some abuse. 80A fuse snapped clean in half

 

[Andy™]

It is unlikely that you will EVER blow it no matter what you do.....

they do blow often - i often have to call DNO to replace a fuse. usually after a fault though and not overload

---------- Post Auto-Merged at 08:11 ---------- Previous post was made at 08:10 ----------

Hi all, im recently qualified so please be gentle! we all have to start somewhereI am looking at a possible rewire for an old property that has a 60 amp supply i can keep the maximum demand down to 60 amp but all the consumer units available have a 100 amp isolator. is ok to use this with a 60 amp supply?

of course you can use less power than the max. its a bit like asking 'i have a 100ltr fuel tank on my van, can i only put 50ltr in it?'

 

[Doc Hudson]

Hi all, im recently qualified so please be gentle! we all have to start somewhereI am looking at a possible rewire for an old property that has a 60 amp supply i can keep the maximum demand down to 60 amp but all the consumer units available have a 100 amp isolator. is ok to use this with a 60 amp supply?

Welcome to the forum. I have moved this to the Student and learning zone as it could not realistically be classed as an "Electricians question". I am not convinced you have grasped a full understanding of equipment rating and the concept of maximum permissible current that an item of equipment can safely carry. (and I do worry that you may also struggle with cable ratings). From basic electrical principals we know that if an item of equipment is capable of carrying and isolating a 100A load, it must also be capable of carrying and disconnecting any load from 1A to 99A as well. You may do well to try and find an experienced electrician to work along side you designing this possible rewire so that you don't make any costly design errors before it is too late. One of our members may be willing to assist. http://www.talk.electricianforum.co.uk/directory-uk-qualified-electricians-electrical-contractors-find-your-local-electrician/2370-find-your-local-electrician-here-list-uk-qualified-electricians.html I would think most members would be willing to help with a couple of hours consultation and advice for a nominal

 

[buddha]

should the db breaker "protect" the main fuse on head,i.e shouldn't the db breaker be less than the fuse on the head??

 

[betty swollocks]

At home mine is a 40A

 

[binky]

Mobile Uploads | Facebook

hopefully link will work - nice photo of meter tail blocks that have been touched together whilst live