Discuss Would you code a 60 amp main switch been fed from a 100 amp BS1361 in the UK Electrical Forum area at ElectriciansForums.net
I carried out a EICR and the main switch for the consumer unit is only rated at 60 amps and the main supply fuse is a BS1361 rated at 100 amps.
Im thinking this should be a C2, what are your thoughts please.
Many thanks
Martin
How do you know it's 100 amps , very rare to get a domestic fuse at that rating normally 60 or 80 amps
It's a shop and I had to pull the fuse to change the main board and this board is Economy 7.
What is the potential danger you have identified?
If you have changed the board/ cu it will be 100amp anyway.?
I was thinking the potential danger is the switching capacity isn't high enough in case of a fault.
Haven't changed this board. I want to change it but need to discuss it with the owner but he doesn't like spending money.
That's not a danger, that is a fact about the inadequacy of the equipment.
What situation can you imagine where the main switch will be required to break fault current?
What is the total load on the board? Is it a fixed load or variable?
There are thousands of cu's out there with 60 amp dp switches backed by 100amp service fuse.
So I should code it as a C3 improvement recommended.
There a four 3kw storage heaters on this board. So a load of 52 amps been drawn.
So the load is under the 60 amp rating of the main switch.
I see your thinking now, so I won't code this.
Sometimes I need to stand back and look at what I'm seeing and thinking from a different angle.
Thank you for your advice.
Martin
There a four 3kw storage heaters on this board. So a load of 52 amps been drawn.
So the load is under the 60 amp rating of the main switch.
I see your thinking now, so I won't code this.
Sometimes I need to stand back and look at what I'm seeing and thinking from a different angle.
Thank you for your advice.
Martin
They'll most likely be 3.4Kw [or 2.55] so you're over 59 amps at 230volts if they're the larger heaters.
Well 230v is the declared single phase voltage throughout the country now even though nothing has really changed [apart from the network becoming ever more stretched to the limit] so that's what we have to base calculations on, I see what you're saying about the heaters though.
I have never seen the voltage at 230v, and am measuring everyday, the lowest I have seen it is 235v. Never seen 216v, but 250v yes. 315v but that was ug fault lol
Here I regularly measure bang on 230V.
That is not the declared voltage, it is the nominal voltage, something which some jobsworth in an office has written down and is impossible to implement. Nothing has changed because it cannot be changed, the whole country has substations with their output fixed at 250/433, there's nothing any jobsworth penpisher can do about that!
It doesn't change the basic physics though, If the stated power rating is at 240V you cannot just replace 240 with 230 in the calculation. The power dissipated will be less at 230V so the current which flows will be less.
Reply to Would you code a 60 amp main switch been fed from a 100 amp BS1361 in the UK Electrical Forum area at ElectriciansForums.net
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