# what Mcb type for hospital wards ?



## simon012 (Jun 18, 2011)

Hi All,

i have a task of changing a very old fuse board and updating it for individual RCBO 30mA 32 amp type C for the ring final circuits. These cover the patient rooms, corridors and other storage/ sluice rooms.
They are wired in 4 mm singles, and my thinking is, each room has beds ( with motors ) , also medical equipment is also plugged in, that incorporates
pumps battery packs. I wanted to minimize tripping so opted for type C.
I am concerned, the the ZS values will be to high for the Max values of the MCB. 
Does anyone have more experience on this selection process, also does the fact the im using individual Rcbo, allow the the ZS values cant always be met.


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## HARRY304E (Sep 15, 2010)

simon012 said:


> Hi All,
> 
> i have a task of changing a very old fuse board and updating it for individual RCBO 30mA 32 amp type C for the ring final circuits. These cover the patient rooms, corridors and other storage/ sluice rooms.
> They are wired in 4 mm singles, and my thinking is, each room has beds ( with motors ) , also medical equipment is also plugged in, that incorporates
> ...


Hello,And Welcome to the forum...:thumbup:


If you could define all of your abbreviations that would help us understand what you are talking about...


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## simon012 (Jun 18, 2011)

HARRY304E said:


> Hello,And Welcome to the forum...:thumbup:
> 
> 
> If you could define all of your abbreviations that would help us understand what you are talking about...


What Im really concearned about is if im using the correct type Mcb. Im choosing the Rcbo as there is room refurbishment going ahead,, and that will cover adding extra cables, sockets etc. The old breakers are type 3. It is light commercial use so im thinking type C is best, as I want to minimize the circuit tripping while patients are hooked up to pumps and other medical equipment while in there rooms. 
I think the ZS values for a type C is around 0.57 off the top of my head, but the test reading is higher than that. About 1.10.


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## klein (Mar 12, 2011)

Nice try.


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## thegoldenboy (Aug 15, 2010)

simon012 said:


> What Im really concearned about is if im using the correct type Mcb. Im choosing the Rcbo as there is room refurbishment going ahead,, and that will cover adding extra cables, sockets etc. The old breakers are type 3. It is light commercial use so im thinking type C is best, as I want to minimize the circuit tripping while patients are hooked up to pumps and other medical equipment while in there rooms.
> I think the ZS values for a type C is around 0.57 off the top of my head, but the test reading is higher than that. About 1.10.


Again, please define your abbreviations and use of terms.


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## frenchelectrican (Mar 15, 2007)

simon012 said:


> Hi All,
> 
> i have a task of changing a very old fuse board and updating it for individual RCBO 30mA 32 amp type C for the ring final circuits. These cover the patient rooms, corridors and other storage/ sluice rooms.
> They are wired in 4 mm singles, and my thinking is, each room has beds ( with motors ) , also medical equipment is also plugged in, that incorporates
> ...





thegoldenboy said:


> Again, please define your abbreviations and use of terms.


 
Golden boy I will try to fill in much as I can with UK terms 

RCBO - non GFCI breaker but few case it will come with GFCI verison and UK and European terms for GFCI is RCD.

Type C is time delay with overload and moderating fast acting on short circuit ( common used with motor or transfomer load and some lighting circuits ) {{ There is 4 class of breaker tripping charatics }}

4mm²= 12 AWG

Ring circuit - a loop for hot conductor so it can able double up the capaity of that circuit { it is not legit in mainland European area but UK are legit unless stated per UK regulations } 

Z value = simauir to short circuit capaity.

There are couple other terms I will let UK electricians answer the rest.

However in France we do use the RCD on some of the Hospital circuits { not all of them used them or used class C or D breaker or fuses unless computer or super senstive electroric loads then use class A or B fuse depending on manufacter.}

Merci,
Marc


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## thegoldenboy (Aug 15, 2010)

frenchelectrican said:


> Golden boy I will try to fill in much as I can with UK terms
> 
> RCBO - non GFCI breaker but few case it will come with GFCI verison and UK and European terms for GFCI is RCD.
> 
> ...



Thanks Marc but Harry asked first. :laughing: I knew there was to much info in there to be a home owner or someone not involved with the trade. We should have a UK translation sticky.


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## frenchelectrican (Mar 15, 2007)

thegoldenboy said:


> Thanks Marc but Harry asked first. :laughing: I knew there was to much info in there to be a home owner or someone not involved with the trade. We should have a UK translation sticky.


 
Yeah one of the days I will or UK guys will post the translation what it means so someone can able figure it out quick to see what we European guys speak of oddball items.

Merci,
Marc


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## frank (Feb 6, 2007)

Simple. Use type C mcb units. Ze not a factor in this instance. Any manufacturere of RCBO will do. Use 30ma rated.

FRank


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## Sparkystevieboy (Jun 30, 2011)

hey guys,are you not required to use 10ma rcd's for hospitals?


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## frenchelectrican (Mar 15, 2007)

Sparkystevieboy said:


> hey guys,are you not required to use 10ma rcd's for hospitals?


 
Yeah we do use the 10ma RCD but only in specfic area but for most genral circuits will use 30ma RCD but couple cirictal circuit will have 100ma RCD but other case will have diffrent class tripping purpose { class C or D }

Merci,
Marc


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## JNV (Jul 22, 2011)

If cables are in metal conduit or trunking then you dont require rcd protection for < 50mm deep reg.
If sockets are not for outside use you dont need rcd protection.
Make sure all the back boxes are earthed and if you are using metel couduit this will help with the Earth Fault loop impedance.
If Still no good then at a larger cost you could replace the socket outlet faces to rcd sockets.
Dont forget you dont require 0.4 disconnection time on fixed circuits >32 amp.


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