Manual Benning IT 110 (page 69 of 80) (English)

577363

Zoom out

Zoom in

1/80

11 Appendix B IT Systems

11.1 Applicable standards

EN 60364-4-41, EN 60364-6, EN 60364-7-710, BS 7671

11.2 Basic information

The IT system is an power supply network which is isolated from the protective conductor. It is

an ungrounded power supply network. Either the network is not connected to earth directly or it

is connected to earth via a relatively high impedance. It is mainly used in areas requiring addition

protection against electrical accidents. A typical area of application are medical operating rooms.

Normally, the network is connected to earth via the high impedance and consists of the capaci-

tances of the lines connected to earth as well as of the capacitances between the primary and

secondary windings of the IT transformer. Occasionally, Y capacitors (EMC) are used in the mains

area of the connected devices. The maximum leakage current can be limited by choosing an ap-

propriate transformer as well as the laying of lines and choosing an optimum earthing with high

impedance.

Depending on the area of application, additional impedance to earth can be generated as shown

ingure11.1orbymeansofspecicdevicesforchargecontrol.Theminimumimpedancevalue

shouldbe100Ω.

An IT network offers additional protection against electrical accidents. If the insulation of a line to-

wards the protective conductor fails due to device failures, incorrect use or improper proceeding,

the network will continue to be safe, but will be converted into a TN/TT system. However, the oc-

currence of another fault would be dangerous. For this reason, the insulation must be monitored

permanently and must be restored immediately after a failure has been detected.

In addition to other protective mechanisms, the IT system normally contains an insulation monito-

ring device (IMD) or a system which emits a warning, if the insulating resistance or the impedance

value falls below the preset limiting value. The limiting value depends on the respective environ-

ment.Atypicalvalueforinstallationsinmedicalroomsis55kΩ.

Insomecountries,itisnotsufcienttomonitoronlytheinsulatingresistanceoftheITsystem.In

this case, the network capacity must be continuously monitored as well.

IEC 60364-4-41 (©IEC): In IT systems, the live parts must be isolated from earth or must be con-

nectedtoearthviaasufcientlyhighimpedance.Thisconnectioncanbemadeeitherattheneut-

ralconductor,atthestarpointofthenetworkoratanarticialstarpoint.Thelattercanbeconnec-

ted directly to the earthing, if the resulting impedance to the earthing is high enough for the given

system frequency. If there is no neutral conductor or star point available, the mains conductor can

be connected to earth via a high impedance.

Report abuse

Libble takes abuse of its services very seriously. We're committed to dealing with such abuse according to the laws in your country of residence. When you submit a report, we'll investigate it and take the appropriate action. We'll get back to you only if we require additional details or have more information to share.

Product:

Forumrules

To achieve meaningful questions, we apply the following rules:

First, read the manual;
Check if your question has been asked previously;
Try to ask your question as clearly as possible;
Did you already try to solve the problem? Please mention this;
Is your problem solved by a visitor then let him/her know in this forum;
To give a response to a question or answer, do not use this form but click on the button 'reply to this question';
Your question will be posted here and emailed to our subscribers. Therefore, avoid filling in personal details.

new questions and answers
new manuals

You will receive an email to register for one or both of the options.

Get your user manual by e-mail

Enter your email address to receive the manual of Benning IT 110 in the language / languages: English as an attachment in your email.

The manual is 6,86 mb in size.

You will receive the manual in your email within minutes. If you have not received an email, then probably have entered the wrong email address or your mailbox is too full. In addition, it may be that your ISP may have a maximum size for emails to receive.

Others manual(s) of Benning IT 110

Benning IT 110 User Manual - German - 83 pages

The manual is sent by email. Check your email

If you have not received an email with the manual within fifteen minutes, it may be that you have a entered a wrong email address or that your ISP has set a maximum size to receive email that is smaller than the size of the manual.

The email address you have provided is not correct.

Please check the email address and correct it.

Your question is posted on this page

Would you like to receive an email when new answers and questions are posted? Please enter your email address.

Info

Benning IT 110 Manual

Product: