DNO fuse 80amp, board dp 100amp

[haptism]

Hi hope someone can help. If a small house's DNO's fuse is rated at 80amps, is it considered bad practice to fit a db with a 100amp dp switch ? As most db's have a 100amp switch I assume this is common practice, also I expect an 80 amp DNO fuse can handle alot more before it blows.

 

[davesparks]

What makes you think a 100A switch on an 80A supply would be a bad idea? What prob
Do you foresee with this setup?

 

[haptism]

What makes you think a 100A switch on an 80A supply would be a bad idea? What prob
Do you foresee with this setup?

That if a fuse was to blow it would be the DNO's before the switch, and replacement of a fuse would be more costly than flicking a switch !?

 

[Simonslimline]

That if a fuse was to blow it would be the DNO's before the switch, and replacement of a fuse would be more costly than flicking a switch !?

Are you saying the main switch would trip?

I hope not.

 

[davesparks]

That if a fuse was to blow it would be the DNO's before the switch, and replacement of a fuse would be more costly than flicking a switch !?

Well you've gone and fallen into the trap then haven't you!

I would recommend researching the definition of what a switch is!

 

[Leesparkykent]

 

[Clive P]

Hi,

I'm waiting with anticipation for the Op to answer Dave's question.

Regards.

 

[davesparks]

Hi,

I'm waiting with anticipation for the Op to answer Dave's question.

Regards.

You don't have to wait too long, he answered it in post 3

You've obviously spotted the little trap I set to help him make a fool of himself

 

[telectrix]

make allowances for the op. he's from london. up north for thinking, down south for dancing. sama:

 

[Megavolt]

Priceless

 

[davesparks]

make allowances for the op. he's from london. up north for thinking, down south for dancing. sama:

OI! [emoji35][emoji35][emoji35]

 

[7029 dave]

OI! [emoji35][emoji35][emoji35]

OI second that.

 

[plugsandsparks]

Its about time they stopped putting current rating on a switch as its way too much detail for todays electrician. What with 63A rated RCDs it can only end in disaster.

The manufacturers should hide it in the small print with a warning " Dear electrician, FFS - this is not an OPD"

 

[Darkwood]

Hi haptism, either your terminology is incorrect or your understanding of how a DP main switch operates is, if its the latter and like suggested in post 5 - you really need to research the differences between

Main DP switches
Fused switches
Switch fuses
MCCB's (with respect to front end protection)

I recommend you have a think about it before your next post..Ill have to be blunt here in saying if you don't understand the basics of operation of a DP main switch then you really shouldn't be a practising Electrician.

EDIT-
PS - Just to offer an olive branch here and some advice regarding why members have responded as such, your standard DP switch often found on your domestic CU is just that 'a switch' - it is solely for means of isolation and provides no overload or short circuit protection, it will not trip under O/L or S/C conditions.

The rating on the front is solely to indicate the max current it can handle so if the DNO fusing is 80amps then the rating of the DP switch is ample at 100amp.

 

[telectrix]

Hi haptism, either your terminology is incorrect or your understanding of how a DP main switch operates is, if its the latter and like suggested in post 5 - you really need to research the differences between

Main DP switches
Fused switches
Switch fuses
MCCB's (with respect to front end protection)

I recommend you have a think about it before your next post..Ill have to be blunt here in saying if you don't understand the basics of operation of a DP main switch then you really shouldn't be a practising Electrician.

EDIT-
PS - Just to offer an olive branch here and some advice regarding why members have responded as such, your standard DP switch often found on your domestic CU is just that 'a switch' - it is solely for means of isolation and provides no overload or short circuit protection, it will not trip under O/L or S/C conditions.

The rating on the front is solely to indicate the max current it can handle so if the DNO fusing is 80amps then the rating of the DP switch is ample at 100amp.

you're getting mellow in your old age. dementia is next. :bigear:

 

[haptism]

Hi all, thanks for the responses, Ive been to Church just now so a bit of delay. I should mention that im no longer a working electrician (I used to be), I now work for Thames Water dealing with water. I thought I would post up this query as on a couple of occasions ive been into properties and noticed the DNO fuse has a lower rating than the db's mainswitch (100a). I was unaware :sweatdrop: that a db's dp main switch would not "trip" under O/L or S/C conditions so you have sorted that for me ! Give yourselves a pat on the back and much thanks for your info.

No dancing at church tonight but there was a good sermon about "salt of the earth"

 

[Simonslimline]

Hi all, thanks for the responses, Ive been to Church just now so a bit of delay. I should mention that im no longer a working electrician (I used to be), I now work for Thames Water dealing with water. I thought I would post up this query as on a couple of occasions ive been into properties and noticed the DNO fuse has a lower rating than the db's mainswitch (100a). I was unaware :sweatdrop: that a db's dp main switch would not "trip" under O/L or S/C conditions so you have sorted that for me ! Give yourselves a pat on the back and much thanks for your info.

No dancing at church tonight but there was a good sermon about "salt of the earth"

Fair play for being honest.

I will be honest as well,and say i am still shocked.

 

[Darkwood]

On that note, I think the thread be best closed as the OP has explained his position and tbh I don't see the thread can move any further forward in a constructive manner.