Sanity Check Required - Do I really need 3 Phase Upgrade?

[ban-all-sheds]

Yep, you said "judging by" so I took that to be a judgement.

I am afraid for some reason there aren't many second hand 17th edition amendment 3 CUs around at the moment, otherwise I would [/QUOTE

i have just bought a Hager 10way for £50.00 on ebay he had two for sale.

DS

No he did not.

 

[ban-all-sheds]

Even though what would have been completely untrue?

"putting a 100A+ load onto a 100A fuse"

 

[securespark]

So why is the 26A on a 20A circuit argument any different?

A 20A radial using 2.5 is a standard circuit. Of course it has the potential to have appliances exceeding 20A plugged into it.

I am failing to see what your issue is.

 

[eveares]

putting a 100A+ load onto a 100A fuse

100A After diversity, then yes you have a problem if you suspect there is a good chance that one will pull a >100A load for a sustained period of time. That's amusing you even have a 100 A fuse and not a 80A or 60A fuse instead.

 

[JohnW2]

100A After diversity, then yes you have a problem if you suspect there is a good chance that one will pull a >100A load for a sustained period of time.

If that were the case, then presumably something would have been wrong with the diversity calculation.

Diversity is necessarily probabilistic, so there is always going to be a finite probability that extreme things could happen - but 'on average' that should not happen unless the diversity calculation itself is flawed.

Kind Regards, John

 

[ban-all-sheds]

So why is the 26A on a 20A circuit argument any different?

It's not.

A 20A radial using 2.5 is a standard circuit. Of course it has the potential to have appliances exceeding 20A plugged into it.

I am failing to see what your issue is.

I'm failing to understand why you do not seem to have a clue about the concept of design current..

 

[ban-all-sheds]

putting a 100A+ load onto a 100A fuse

100A After diversity, then yes you have a problem if you suspect there is a good chance that one will pull a >100A load for a sustained period of time. That's amusing you even have a 100 A fuse and not a 80A or 60A fuse instead.

It would probably be of benefit to the way this topic develops if people would actually read properly.

 

[securespark]

I know all about design current.

But how does that stop a 20A circuit drawing 26A?

 

[ban-all-sheds]

It doesn't.

What is your point?

 

[securespark]

Weren't you banging on about how you cannot expect a 20A radial to be loaded to 26A?

 

[ban-all-sheds]

Doubt it.

But feel free to show where you think I said something I didn't.

 

[stuartR1963]

Worth pointing out that 3 phase isn't always available in some parts. You might find that the main cable that runs along your road supplying your house is only single phase.If it is only single phase and you were to go for 3 phase it would involve digging up the roads and running a new cable either back to the substation wherever it may be or at the top of your road at the junction where the main for your road is tee'd off the main 3 phase and neutral cable. Either way it will be at your expense and it won't be cheap!. just worth pointing out

Single phase is usually more than enough for most domestic properties.you will probably be fine.

 

[PBC_1966]

Worth pointing out that 3 phase isn't always available in some parts. You might find that the main cable that runs along your road supplying your house is only single phase.

In some cases you might find that the cable running along the street provides two phases. This is common in older districts of cities which originally had d.c. mains supplies. When converted to a.c., the electricity boards would run a new 4-core 3-phase feeder along a main thoroughfare, but leave the existing 3-core branch cables off into the side streets of houses, so one street of homes would be on red & white phases, another on red & blue, and a third on white & blue.

Out in the country, you might not even have a 3-phase high-voltage feed into the area, just a single-phase spur line. For exceptionally heavy residential loads, you might still have the option of getting a 3-wire 240/480V service to distribute the load though.

 

[eveares]

red & white phases, another on red & blue, and a third on white & blue.

They are not standard colours for the UK; Used to be Red (1st L), Yellow (2nd L) Blue (3rd L) and Black (N), now it is Brown (1st L), Black (2nd L) and Grey (3rd L) and Blue (N)

you might still have the option of getting a 3-wire 240/480V service to distribute the load though.

480V!? 230v x 1.732 = 400V OR 240v x 1.732 = 415V

 

[securespark]

Doubt it.

But feel free to show where you think I said something I didn't.

You were complaining in another thread about how it was inconceivable to think that a designer would design a 20A radial circuit if there was a possibility of the load exceeding that.

But I can't find it now.