Type D RCBOs

[johnnycash126]

Dear all,

I have to protect a 13 amp ring main which is currently protected by a type b rcbo.The circuit is going to be used by step down transformers from the US.Notorious for tripping on start up.I thought a change to a type D rcbo would cure this,however neither MEM or Crabtree make a type D RCBO.This makes me think that perhaps im not allowed to do this.

Anyone any experience of this?

 

[iamelectric]

i have only ever used 3 phase type D mcbs

 

[MDJ]

Do you have to have an RCBO, I would avoid one of those at all costs and try to design the circuit so it does not require one, they are fine in their own right but for a Transformer? hmm how about no chance unless the earthing requirement or enviroment means one has to be used.

 

[Pete999]

Will changing the type of rcbo from a b to a d inter fear with the disconnection times? I would have thought that the best bet would be to feed these transformers from a dedicated circuit specifically designed for this type of use, sounds like someone wants you to do a cheap fix which probably isn't safe

 

[johnnycash126]

Can I then replace the type B rcbos with type d MCBs?

 

[Pete999]

Whats the reason for that it?

 

[MDJ]

Dear all,

I have to protect a 13 amp ring main which is currently protected by a type b rcbo.The circuit is going to be used by step down transformers from the US.Notorious for tripping on start up.I thought a change to a type D rcbo would cure this,however neither MEM or Crabtree make a type D RCBO.This makes me think that perhaps im not allowed to do this.

Anyone any experience of this? Can I then replace the type B rcbos with type d MCBs?

you have been a member for 3 and a half years so I assume you are a competant spark yes? that said we are now going down the inexperienced route, what a silly question your last post was, think about what you said and then you will see what I mean.

 

[johnnycash126]

The americans are coming.And they bring step down transformers for their equipment.ie hairdryers,tongs etc.Historically,they will trip our type B MCBs.Now we have anew installation with type B rcbos. Again,I expect the breakers to trip under starting current.

 

[johnnycash126]

you have been a member for 4 and a half years so I assume you are a competant spark yes? that said we are now going down the inexperienced route, what a silly question your last post was, think about what you said and then you will see what I mean.

Dont assume.You know what that makes.I was an electrician im now in a different role.

 

[MDJ]

Whatever, a ridiculous question, first a D rated rcbo now an MCB, ever heard of a design? anyhow good luck to you whatever you decide.

 

[Pete999]

Even so mate an rcbo provides overload and earth leakage protection so if its just inrush thats tripping your rcbo changing it to a cb of the same type (b,c,d) wont make the slightest difference

 

[R G]

To put this on a circuit that your suggesting is not good , best on its own circuit especially if its tripping out an rcd . Design it and you won't need the RCBO,,

 

[johnnycash126]

Ok I understand that,but could i then change the rcbo to an MCB type d and then provide earth leakage protection by fitting RCD sockets?

 

[MDJ]

DIY alert team

 

[R G]

Ok I understand that,but could i then change the rcbo to an MCB type d and then provide earth leakage protection by fitting RCD sockets?

Are you serious , or a windup ,