Wich fuse to?

[dmills]

Since when did CE require double pole fusing?
The fuse goes in the phase conductor, never the neutral.

Now it might be that there is some local standard in countries with non polarised plugs that requires double pole fusing, but nothing in the half dozen or so EU wide standards implied by being CE marked does (At least not for standard stuff - there may be something special in for some obscure edge cases (medical electronics??)). .

Regards, Dan.

[coastredwood]

Thanks.

I`m sure, that this amp came out from the factory with only one fuse. Lets keep it sipmle.

So you say, that brown (phase) wire shoud have fuse..


I have an small diy amp, wich i bought from one of my old friend. It came with 2-core power cable (blue and brown) and it has fuse on the blue one. Why is that so?

Why this aps problem came up.
I had it playing for few weeks, but one moment tiny blast and light effect took place. Consequence was short circuit (not sure if it is the right termin) in house electric system and whole house was dark.
And blue wire (neutral) broke from its soldering place and overheating marks were on it.

Is it possible that the reason was just wrong fuse? (used one old one)

[Sonusthree]

Originally posted by coastredwood
......... And blue wire (neutral) broke from its soldering place and overheating marks were on it.

Is it possible that the reason was just wrong fuse? (used one old one)

Fuse is too big = not safe
Fuse is too small = safe but unreliable

Fuses melt when too much power goes through them. Usually because of a fault.

You should get it checked by a professional to be safe.

[Pjotr]

Originally posted by dmills
Since when did CE require double pole fusing?
The fuse goes in the phase conductor, never the neutral.

Now it might be that there is some local standard in countries with non polarised plugs that requires double pole fusing, but nothing in the half dozen or so EU wide standards implied by being CE marked does (At least not for standard stuff - there may be something special in for some obscure edge cases (medical electronics??)). .

Regards, Dan.

The fuse should protect the customer/user in case of overload and malfunction of the apparatus, i.e. for fire and hazardous voltages.

In many EU countries you can plug-in the mains plug 2-ways. That requires fuses in both lines for Class-1 apparatus. Since CE compliance applies to all EU countries it requires 2 fuses to comply with CE.

Coastredwood gave a good example where it went wrong: The fuse of the amp should have gone, not the fuse of the house.

Cheers

[coastredwood]

Originally posted by Pjotr


The fuse should protect the customer/user in case of overload and malfunction of the apparatus, i.e. for fire and hazardous voltages.

In many EU countries you can plug-in the mains plug 2-ways. That requires fuses in both lines for Class-1 apparatus. Since CE compliance applies to all EU countries it requires 2 fuses to comply with CE.

Coastredwood gave a good example where it went wrong: The fuse of the amp should have gone, not the fuse of the house.

Cheers

Great information, thanks.

So, do You recommend to use two fuses? But I think it can`t be just that easy, right?

Can anybody comment the fuse placement on phase wire. Are you 100% sure?
Why did the neutral wire blowed appart when this little accident took place?

[Pjotr]

Hi Coastredwood,

Probably because it was connected to live without any fuse and there was a short to ground somewhere. Even a wrong fuse, say a 10A one, should have tripped before the house fuse.

I strongly recommend to find the cause of the short. But because of your questions here, let have a look at it by an experienced guy in this matter. Safety is not something to play around with.

[coastredwood]

Originally posted by Pjotr
Hi Coastredwood,

Probably because it was connected to live without any fuse and there was a short to ground somewhere. Even a wrong fuse, say a 10A one, should have tripped before the house fuse.

I strongly recommend to find the cause of the short. But because of your questions here, let have a look at it by an experienced guy in this matter. Safety is not something to play around with.

Finding professional who coud fix it in 30 minutes is good idea.

Alltough connectind a power cable to transformer and chase, and adding fuse is not rocket sience.

But yes, they say, electricity kills just once.

[dmills]

Originally posted by Pjotr

In many EU countries you can plug-in the mains plug 2-ways. That requires fuses in both lines for Class-1 apparatus. Since CE compliance applies to all EU countries it requires 2 fuses to comply with CE.
Cheers

I cannot find anything in the Low Voltage Directive requiring double pole fusing and there is nothing in the UK implementation of this needing it.

For class 1 equipment, is it actually the case that any of the common EC connectors are nonpolarised?

The CEE 7-7 (Schuko, France, Germany and others) is polarised (Two different ways depending on the country), as is the BS1363A (UK 13A). In fact on a cursory look, the only EU country I can find using non polarised plugs for class one appliances is Italy.

I can only assume that the Italians require some other means of protection (RCD?).

I suspect that if you look at the vast majority of recent CE marked kit sold in the EU, you will find only one mains fuse.
I have had several items submitted to test houses for CE, and have never even heard of a problem with single pole fusing.

Regards, Dan.

[Juergen Knoop]

no!
German mains plugs are not polarised and you don't need two fuses here.
It doesn't matter, if the equipment fuse breaks neutral or live. The current is interrupted anyway.
A short to case is something different.
The protective earth has to be capable withstanding a fault current up to 16A until the houses mains circuit breakers or fuses jump in.
RCDs are additional protection only and were not mandatory in the past.
You can not expect them and of course nobody constructs equipment with them in mind.
regards

[dmills]

I stand corrected.

My memory must be going, because I seem t remember the last time I took a tour to Germany, and it was Schuko and CEE 17 (C-Form) all the way.

<Shakes head and wonders away muttering to himself>

Regards, Dan.