Selecting which breaker trips first by trip curve

[John Sheppard]

Hello i'm in the EU and i will be getting 230v 40A service in my holiday house (previously was 3ph)
My issue is that the mains come in at the pole just outside the property and i'm required to have a 40A breaker there (so far so good)
The wire then comes to my house which is about 70 yards away and goes into the main electrical panel .

Now if i put another 40A breaker in the house i suspect the first breaker outside will trip first which means i'll have to go out, possibly in bad weather to reset it (undesirable)
i could put a 32A breaker in house but that will deny me the use of almost 2KWs which i would rather have

Is there a way to have a 40A breaker in the house but also make sure that this one always trips first instead of the one that's outside , by using breakers with different trip curves?


I hope the question makes sense i appologize for my english
Thank you

 

[Megawatt]

Hello i'm in the EU and i will be getting 230v 40A service in my holiday house (previously was 3ph)
My issue is that the mains come in at the pole just outside the property and i'm required to have a 40A breaker there (so far so good)
The wire then comes to my house which is about 70 yards away and goes into the main electrical panel .

Now if i put another 40A breaker in the house i suspect the first breaker outside will trip first which means i'll have to go out, possibly in bad weather to reset it (undesirable)
i could put a 32A breaker in house but that will deny me the use of almost 2KWs which i would rather have

Is there a way to have a 40A breaker in the house but also make sure that this one always trips first instead of the one that's outside , by using breakers with different trip curves?


I hope the question makes sense i appologize for my english
Thank you

Hi and welcome to the forum my advice is to install a 40 amp GFCI breaker in your home. It should trip first. Good luck

 

[John Sheppard]

Thanks i have one installed already but if i understand correctly it only protects from a ground-neutral fault and not an overcurrent situation? My question was about the one that trip when you exceed the current specified here we call them "automatic fuses" but i guess they're called circuit breakers in english or maybe not? sorry my english is bad

 

[telectrix]

might be better to fit a slow blow 40A fuse at the pole instead of a breaker. that should entail the breaker in the house tripping instead of the device at the pole.

 

[buzzlightyear]

considering that the house would be a TT system a up front RCD will be required from the services .like most places like Spain . and agree the post above .

 

[Lucien Nunes]

Different curves of standard MCB (yes, MCB or circuit breaker is correct) typically made to EN 60898, refer mainly to how the MCB behaves with a short term heavy overcurrent such as a short-circuit fault current or the starting surge of a large motor. For example, a D40 will allow a larger surge through than a B40 without nuisance tripping, but requires a lower loop impedance to ensure it operates.

But it is only the instantaneous tripping behaviour that differs between the two. When a prolonged low-level overload occurs, such as a load of 60A due to too many appliances being switched on at once, the D40 is as as likely to trip first as the B40, because this current is below the instantaneous trip threshold. Therefore you cannot use different curves of the same type of MCB to determine the tripping order when overloaded.

As mentioned above, a fuse upstream amd MCBs downstream is sometimes practical, although you should not routinely subject fuses to long low overloads by design. On my boat, I have cheated a little. I have recalibrated some MCBs downwards so that under normal temperature conditions I can be fairly sure that my '14A' will trip before a normal 16A in the marina, but even so, the tolerances are too wide to guarantee this with all other breakers.

 

[plugsandsparks]

Another vote for fuse. This is how my place is, also have a tiny supply which struggles with a/c, oven and kettle. MCB in house trips first, fuse has only gone once, when i blew it up by mistake... :-(

 

[radiohead]

You say you are required to have a 40a device at the supply end? Is this actually the case? In the UK overload protection can be at the load end, so a 40a breaker could be installed in the home, with a 63a (for example) at the supply end. Overload protection is afforded by the load end device.

 

[John Sheppard]

Yes MCB thank you Lucien .
I was required to place an MCB AND a GFCI at the supply end because i do have some lights and a couple sockets in the yard that are pulling directly from the main line.

"Therefore you cannot use different curves of the same type of MCB to determine the tripping order when overloaded"
Is there another specification of MCB that have different trip times at slow overload condition? Or perhaps different manufacturerers? All of my current ones are from Hager

I thought about placing an actual fuse but aren't they more likely to blow out faster than the MCB would trip when at slight overload say 45amps?


Also i cannot use a 63A at the supply end because the meter has it's own breaker and AFAIK it's 40A also (the contract says 40amps so i just assume they have a 40amps on inside the meter) and i would rather not "abuse" (for lack of a better word) that to not break it which will cost me a lot as the company will charge me with a new meter most likely.

 

[Megawatt]

Hello i'm in the EU and i will be getting 230v 40A service in my holiday house (previously was 3ph)
My issue is that the mains come in at the pole just outside the property and i'm required to have a 40A breaker there (so far so good)
The wire then comes to my house which is about 70 yards away and goes into the main electrical panel .

Now if i put another 40A breaker in the house i suspect the first breaker outside will trip first which means i'll have to go out, possibly in bad weather to reset it (undesirable)
i could put a 32A breaker in house but that will deny me the use of almost 2KWs which i would rather have

Is there a way to have a 40A breaker in the house but also make sure that this one always trips first instead of the one that's outside , by using breakers with different trip curves?


I hope the question makes sense i appologize for my english
Thank you

I’ve never heard of having to put breakers on a pole for the power company but still since you already have RCD or GFCI protection and have a ground fault or an overcurrent situation it will trip in the home before the one on the pole. Why does the power company require this breaker ?