Singel Pole vs. Double Pole MCB

...or to use two separate MCB's, one for line and one for Neutral.....That is also unsafe.

NO- Must be common trip. -- JHF

I don't think you understand my English somehow!! I will repeat exactly what I wrote before, here:-

...or to use two separate MCB's, one for line and one for Neutral.....That is also unsafe.

Read the last few words again!!!

Now do you understand fully?

I was "adding" a comment of what was a list of unsafe procedures, they had forgotten this scenario.......

Try reading slower.

You were not alone either, someone else has trouble with English I noticed......

Msamad, while this is true in North America, it is not true in the rest of the world. They have different types of distribution systems, some of which REQUIRE switching of the Neutral.

coolyar, this means that your answer is dependent upon the type of power distribution system you have, as in IT, TT, TN, etc (don't use those literally, I am no expert on IEC systems. I'm going by memory and have no immediate resources available.)

It is true that some installations require double contact switching, but not necessarily double pole MCB, However Earth leakage protection is always double pole

Bazzer

Hi Coolyaar,

I completely agree with "msamad" in the priciples he've posed.... but what I'd like to add is that we usually use the single-pole MCB rather than double-pole one when there's no enough room in the main distribution box(as most of them are limited in size)..... bear in mind, every rule has exceptions.. when we deal with an MCB supplied with protection against Ground Fault(in this case, it's named RCD or RCCB and they're installed in bath rooms and other wet places) , hence you find such Circuit Breakers as Double-pole..

Hope this helps

It depends upon the type of your network. If the network is TN-C, then one must not break the neutral and thus shall go for a single pole MCB. In TN-S and in TT, then it is safe to go for SPN or DP MCBs.

Just to clarify, in what instance/situation would it be required to use DP? As from the replies above, there are restriction to use of protection on neutral so it would seem safer just to go with Single Pole.

For electrical equipment located in hazardous area, the neutral must also trip when the phase trips. TN-C wiring method is also not allowed there.

To wire the neutral through an overcurrent protection device falls outside British Standard 7671 and potentially could lead to electrocution/death.

My experience with single pole RCBs (Residual current breakers) in a domestic setting, drove me up the wall. So if I ever have control over a future installation I will ensure that the breakers are double pole. The problem was that every time we were working on one of the circuits we turned off that breaker, but, if we inadvertently shorted earth and neutral, the main breaker would activate, and, turn off all the power.

Please, PLEASE get a hold of a copy of your local electrical standards and regulations, many of the questions you ask here on CR4 you can answer yourself if you would just read these important documents.