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A company that is looking to add equipment in their facility informed me that they have an IT ground. The ground can actually result in damage to electronic components if they aren't compatible. About the only thing I have come up with is this Wikipedia article that mentions it:

In an IT network, the electrical distribution system has no connection to earth at all, or it has only a high impedance connection.

Of course you have to take Wikipedia with a grain of salt but the information supplied isn't very in depth. I want to make certain I have a clear understanding of this.

What makes electronics such as servo drives and PLCs I.T. ground compatible?

wallyk
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Rob
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    How about a link to where you read it? – Andy aka Mar 06 '18 at 15:53
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    How about an in depth question with relevance? – Tony Stewart EE75 Mar 06 '18 at 16:00
  • A company that is looking to ad equipment in their facility informed me that they have an IT ground. The ground can actually result in damage to electronic components if they aren't compatible. About the only thing I have come up with is a wikipedia article that mentions it. Of course you have to take wikipedia with a grain of salt but the information supplied isn't very in depth. I want to make certain I have a clear understanding of this. – Rob Mar 06 '18 at 16:02
  • https://en.wikipedia.org/wiki/Earthing_system#IT_network – Rob Mar 06 '18 at 16:04
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    Welcome to EE.SE, Rob! I've taken then liberty of including the clarifications you've given us in the comments in your original question so it doesn't attract any more close votes. Cheers! – Ricardo Mar 06 '18 at 16:37

1 Answers1

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In power electrics, IT designates a grounding scheme in which there is a deliberate impedance between the transformer's star point and ground. It is used to control fault currents and provide a means to alarm on first fault without forcing an immediate shutdown.

See for example Cahier technique no. 178 - The IT earthing system (unearthed neutral) in LV (PDF) for some discussion.

It is popular in applications like hospital operating rooms where the power tripping off without warning is more than a little unwelcome, but is also used in heavy industry where there are steps that must be taken to avoid damage before the plant can be shutdown.

wallyk
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Dan Mills
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    During the single fault condition the phase-ground voltage on non-fault phases will increase significantly. Presumablly this is what causes the risk of equipment damange. – Peter Green Mar 06 '18 at 20:29
  • Sounds about right, the elephant in the room usually being the input suppression caps and MOVs (Especially if some numpty has connected a MOV between phase or neutral to ground, seen it, stupid thing to do). The class Y caps should take the abuse, but there are strange things out there. – Dan Mills Mar 07 '18 at 09:24