Type of MCB to be used inside the EX e street Lighting Junction box

[sramesh]

Good day to you

We propose to introduce a MCB inside the Street Lighting Junction box ( EX e Certified) installed in Hazardous area.

Contractor propose to use a normal MCB with C curve.

The query is whether MCB should also be Ex cerified. Ex panel manufacturers like Stahl are providing Ex rated MCBs inside the control Junction Box.

Request your clarification.

Regards
Ramesh

 

[ScottyUK]

I'm pretty sure the only way you could use a standard MCB would be inside an Ex'd' box, where any ignition caused by MCB operation would be contained in the flameproof enclosure. Other than that you will need certified components.


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If we learn from our mistakes I'm getting a great education!

 

[Kiribanda]

sramesh,

It is very strange to hear that there are MCBs which are Ex e certified? In fact STAHL makes Ex e and Ex d enclosures with normal MCBs (Trip curve depends on the user) inside. But the MCBs are not Ex e or Ex d certified. How can you certify a MCB as Ex e or Ex d?

Since it is a classified area you can install a distribution panel with MCBs housed in a Ex e or Ex d certified enclosure.

 

[sramesh]

Good day to you

Please refer the attached files, which specifies that any spark producing component shall be Ex certified.

Regards
Ramesh

 

[ScottyUK]

Kiribanda,

Those MCBs are a special design and are expensive. They have little in common with the standard European MCB. I have not seen a Stahl Ex 'e' enclosure with standard MCBs - can you post a reference to that product line?



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If we learn from our mistakes I'm getting a great education!

 

[sramesh]

Kiribanda,

The attached file is on Ex rated MCB of COOPER for your reference

Regards
Ramesh

 

[IndianTechEngg1001]

These MSBs are normally used in equipments panels (for like chargers/ UPS/ Electronic/ Telecommunucation systems) where it is not always poessible t provice e/i enclosures on them.

If someone wants to use these MCB inside a protected enclosure then also these is no problem. But even if a normal MCB is used inside it, this can also fulfill the purpose.

 

[ScottyUK]

From IEC 60079-7

Increased safety "e"
Type of protection applied to electrical apparatus in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks in normal service or under specified abnormal conditions

NOTE 1 This type of protection is denoted by "e". The “additional measures” are those required for compliance
with this standard.

NOTE 2 Apparatus producing arcs or sparks in normal service is excluded by this definition of increased safety.


You can not use a standard MCB in an Ex'e' application.


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If we learn from our mistakes I'm getting a great education!

 

[Kiribanda]

ScottyUK,
Please see the attachment.Unfortunately I donot have inside picture.I referred to these Ex d or Ex e enclosures where normal mcbs (IEC60898) or contactors are wired.The cable entry can be direct entry to an Ex d enclosure with Ex d glands or indirect entry terminating to an Ex e terminal block inside Ex e enclosure.If such indirect entry is used then there is a seal between Ex e and Ex d chambers.

 

[Kiribanda]

ScottyUK,
oops,lost the attachment.
Please see the attachment.Unfortunately I donot have inside picture.I referred to these Ex d or Ex e enclosures where normal mcbs (IEC60898) or contactors are wired.The cable entry can be direct entry to an Ex d enclosure with Ex d glands or indirect entry terminating to an Ex e terminal block inside Ex e enclosure.If such indirect entry is used then there is a seal between Ex e and Ex d chambers.

 

[sramesh]

Kiribanda,

Good day to you

My query is using only EX e box for installing MCB, switching device which can create spark.

Your attachment of Ex d e box has a separate Ex d compartment where any normal switching devices can be installed. it ha sno issues as inside Ex d box there is no restriction. I Contacted STAHL and they have confirmed that any devices inside Ex e type box shall have individual certification.( refer attached file)

Regards
Ramesh