transformer tripping mcb

[sajeel]

Evening peeps,

Got a question i need help with a friend of mine has an american food processor the unit is 1000w 110v i purchased a 3000 w 230 to 110v step down and stepup transformer have set to 240v on input and using 110v output. I am finding due to surge sometimes on start up the transformer will trip a b32 mcb, i know mcb could be replace for type c, however rather carry this out on friends kitchen circuit, is there not another solution such as using plug in rcd or placing a type c mcb inline so consumer unit mcb is not tripped, i await replies and sugesstions along with critisms as usual

 

[telectrix]

replace the B32 with a C type. my 3kVA site tranny also trips a B32.

 

[Steviec1]

replace the B32 with a C type. my 3kVA site tranny also trips a B32.

Ideally, transformers should be on a D curve due to high inrush

 

[westward10]

If you are going to replace the device you need to ensure fault protection is still maintained if there is no rcd in place.

 

[sajeel]

thanks so looks like a type c or d mcb, my question was if fit inline mcb to tranny power source will that stop the b32 tripping, if not i suppose not that difficult to replace inside consumer unit.

 

[sajeel]

consumer unit is split load rcd

 

[Pete999]

Evening peeps,

Got a question i need help with a friend of mine has an american food processor the unit is 1000w 110v i purchased a 3000 w 230 to 110v step down and stepup transformer have set to 240v on input and using 110v output. I am finding due to surge sometimes on start up the transformer will trip a b32 mcb, i know mcb could be replace for type c, however rather carry this out on friends kitchen circuit, is there not another solution such as using plug in rcd or placing a type c mcb inline so consumer unit mcb is not tripped, i await replies and sugesstions along with critisms as usual

Quite possibly it's the inrush current tripping the c type cb swap it for a D type

 

[sajeel]

At the moment is tripping b mcb intermittent not every power on will try c mcb if not type d, from my calculation c should be enough. the unit is fitted with a c16 mcb at front

 

[Steviec1]

consumer unit is split load rcd

It will be no use putting the D type in the line following a B breaker, you will need to put the D type in the CU

 

[sajeel]

It will be no use putting the D type in the line following a B breaker, you will need to put the D type in the CU

Thought so just wanted to confirm. Any ideas where to buy type d as they seem to be rare ?

 

[westward10]

Is fault protection maintained with a type C or D. If you have no rcd protection in place a type D is a bad idea as they are not suitable for the protection of general socket outlets.
What make is the consumer unit.

 

[Strima]

Do you have the manufacturers information to calculate what curve MCB is required?

Also is the Zs of the final circuit sufficiently low for a type C or D.

Also a type D isn't really suitable for domestic socket outlets, I would consider running in a sperparte circuit if a type D is required.

Much easier to buy a food processor at the correct voltage and frequency rating, there's quite a large selection available...

 

[sajeel]

The consumer unit is mk split load with 2 rcds.

 

[westward10]

MK have never produced type D devices.

 

[Steviec1]

Thought so just wanted to confirm. Any ideas where to buy type d as they seem to be rare ?

Any wholesaler should be able to order this for you

 

[pc1966]

Type D are rare as few loads need them, and for higher current type D MCBs it can be hard to meet the 0.4s disconnection time for final circuits (you need quite a low Zs to hit the magnetic trip to meet that specification).

They tend to be for protecting sub-mains (when 5s on the thermal part is OK), but are not as good as fuses there in terms of selectivity with downs stream MCB/RCBO. Or for high inrush things like big transformers and motors, again not a common domestic type of load.

Also if you are regularly switching a load that needs a type D MCB due to inrush you will find you switch has a short life...

 

[sajeel]

Good pointers people am will look into type c mcb, to be honest have not taken tranny to friends house yet might not even trip, just tested at his home

 

[Steviec1]

Type D are rare as few loads need them, and for higher current type D MCBs it can be hard to meet the 0.4s disconnection time for final circuits (you need quite a low Zs to hit the magnetic trip to meet that specification).

They tend to be for protecting sub-mains (when 5s on the thermal part is OK), but are not as good as fuses there in terms of selectivity with downs stream MCB/RCBO. Or for high inrush things like big transformers and motors, again not a common domestic type of load.

Also if you are regularly switching a load that needs a type D MCB due to inrush you will find you switch has a

Good pointers people am will look into type c mcb, to be honest have not taken tranny to friends house yet might not even trip, just tested at his home

Schneider produce d type breakers 1 pole up to 60A din rail mount.
I have one of these

 

[Steviec1]

Schneider produce d type breakers 1 pole up to 60A din rail mount.
I have one of these

They will also supply 32A