Merlin Gerin c800n MCCB Dial Settings

Simple questions usually require simple searches. Did you Google on your thread title? Obviously not or you would have found this:

http://www.neweysonline.co.uk/neweys/pdf/Merlin_Gerin_Circuit_Breaker_Application_Guide_Technical.pdf

If you do some of the simple stuff first you'll get better answers here, otherwise accept what comes your way. Welcome to CR4.

It's alphabet soup....why they can't print a simple explanation on the breaker is a mystery to me....I would contact Schneider Electric and get some support...

They are standard industry symbols. Just not North American standards.

Be careful changing those settings.

They may have been set that way due to cable sizes and routing through the building.

From memory the "T" is time before an action takes place. Changing them will alter Open & Close times.

The "I" settings are your danger zone as they may have been set low due to de-rating of the cable the breaker protects. If you increase them you may risk a fire.

Personally I would contact Schneider first to work out what the settings are & their meaning.

Second, contact either your site electrician (if it is not you) or an electrical engineer to work out why it is set as it is and IF they can be safely changed.

Once you have engineering approval you can make changes or if not you will at least know why not!

Be careful.

Regards,
Sapper

Hey Guys,

Cheers for all your help, yes we were in the process of a complete assessment of the installation. Its a Feeder for the Main Switchboard in a boating Marina, has been fine for years but trips when there is alot of boats moored .There is 5 X 160A sub-mains to various pillars etc. When we attended there was next to no load, but on a busy day its tripping. As the modern boats have more and more electronics / A/C etc the marina has been compensating for the demand but we believe no attention has been made to the Main Switchboard.Some boats required a 5pin 63A Outlet (90' Yacht)

we wont be adjusting anything unless we can, we are going to contact the supply authorities due to it being fed by there transformer (most this size are 400A so it will have to stay wound down) plus we have no access to the incoming mains as they are sealed by them. Incoming cables may be under size too, but rest assured a full investigation will be done before anything is touched.

Thanks once again for all your help!

Cheers

I confirm PeterT answer .

The trip unit of this Compact C800 range is named ST305S .

If you cannot find its operation manual, send me yr email, I can forward it to you