Siemens SENTRON User manual

SENTRON
www.siemens.com/rccb
Residual current
protective devices
Technology primer
Edition 06/2018

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Be it protecting, switching, measuring or monitoring – components for
low-voltage power distribution from Siemens offer just the right device
for all applications in the electrical installation field. Whether for use in
industry, infrastructure or buildings, these products guarantee a maximum of
flexibility, ease of use and safety.
So you can keep the entire power supply safely under control.
This is especially important when it comes to selecting and installing the
appropriate residual current protective device. With this primer, we provide
you with a simple tool for perfectly adapting the respective residual current
circuit breaker to the requirements of the electrical installation in question.
Apart from general information on residual current protective devices, it
contains important details regarding installation and use. You are therefore
sure of always selecting the right device.
Preface

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1. Product portfolio 6
2. Introduction 8
3. Protection through residual current protective devices 9
3.1 Additional protection with In ≤ 30 mA
(previously “Protection against direct contact”) 9
3.2 Fault protection (previously “Protection against indirect contact”) 13
3.3 Fire protection 14
4. Residual current protective devices 15
4.1 Types of RCCBs 15
4.1.1 Type AC 17
4.1.2 Type A 17
4.1.3 Type F 17
4.1.4 Type B 17
4.1.5 Type B+ 18
4.2 Classification of residual current protective devices 18
4.3 Basic design and method of operation 21
4.3.1 Type A RCCB 21
4.3.2 SIQUENCE universal current-sensitive RCCB Type B and Type B+ 24
4.4 Features and application areas 25
4.4.1 RCCB 25
4.4.2 RCBO Type AC, Type A and Type F 26
4.4.3 SIQUENCE universal current-sensitive RCCB Type B and Type B+ 29
4.4.4 SIQUENCE universal current-sensitive RCBO Type B and Type B+ 34
4.4.5 RC units for installation on miniature circuit breakers 35
4.4.6 SIGRES RCCBs (for harsh ambient conditions) 36
4.4.7 Type
Ksuper-resistant 37
4.4.8 Type
Sselective 39
4.4.9 Versions for 50 to 400 Hz 40
4.4.10 Versions for 500 V operational voltage 40
4.4.11 RCCB with left-side N connection 40
4.5 Additional components for RCCBs 41
4.5.1 Remotely controlled mechanism (RC) 41
4.5.2 Auxiliary switches 43
4.5.3 Additional components 43
Contents

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5. Notes on installation and use 44
5.1 General notes 44
5.1.1 Selection of protective devices 44
5.1.2 Use of residual current protective devices 46
5.2 Choosing the right residual current protective device 48
5.2.1 Type A, Type F or Type B / Type B+? 49
5.2.2 What protection goal must be achieved? 49
5.2.3 What electrical interference occurs and how is it handled? 50
5.3 Special features regarding the use of SIQUENCE universal current-sensitive
RCCBs (Type B and Type B+) 53
5.3.1 Applications 53
5.3.2 Residual currents at various fault locations, with a frequency
converter (FC) as an example 54
5.3.3 Configuration 61
5.3.4 Causes of excessive leakage currents and possibilities of reducing
them 62
5.4 Back-up protection 64
5.5 Protection against thermal overload 66
5.6 Troubleshooting 67
5.7 4-pole RCCBs in a 3-pole network 68
6. MRCDs and RCMs 69
6.1 Modular residual current devices (MRCDs) 69
6.2 Residual current monitoring devices (RCMs) 70
7. Outlook 73
8. Sources 74
9. Appendix 75
9.1 Key terms and definitions (according to DIN VDE 0100-200) 75
9.2 Power systems and protective devices 78
9.2.1 TN system 79
9.2.2 TT system 80
9.2.3 IT system 82
9.2.4 Summary 83
9.3 Key terms and definitions for specifying the switching capacity 84
9.4 Installation regulations for electrical installations with residual current
protective devices 85
10. List of figures and tables 87

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Product portfolio
1. Product portfolio
Residual current circuit breaker
(RCCB) 5SM3 / 5SV
• Type AC, Type A and Type F
• In= 16 … 125 A
• In = 10 mA … 1 A
• 2-pole (1+N) and 4-pole (3+N)
• N connection at left and right
• SIGRES version for harsh ambient
conditions
• Version Kand S
• Version for 500 V
• Version for 50 … 400 Hz
SIQUENCE residual current circuit
breaker (RCCB) 5SM3/5SV3
• Type B, Type B+
• In= 16 … 80 A
• In = 30, 300 and 500 mA
• 2-pole (1+N) and 4-pole (3+N)
• Version Kand S
• including SIGRES functionality
SIQUENCE residual current breaker
with overcurrent protection (RCBO) 5SU1
• Type B, Type B+
• In= 100 … 125 A
• In = 30, 300 mA and 1 A
• 4-pole
• Circuit breaker characteristic
C and D
• Rated switching capacity 10 kA
• Version Kand S

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RC unit for combination with a
miniature circuit breaker 5SM2
• For mounting on a miniature
circuit breaker
• Combined electric shock and line
protection
• Type AC, Type A and Type F
• In= 0.3 … 100 A
• In = 10 mA … 1 A
• 2-, 3- and 4-pole
• Version Kand S
RCBOs;
combination units 5SU1
• Combined electric shock and line
protection
• Type AC, Type A and Type F
• In= 6 … 40 A
• In = 10 … 300 mA
• Circuit breaker characteristic B and C
• Rated switching capacity 4.5 kA,
6 kA and 10 kA
• 1+N-pole, 2-pole
• N connection at right and left
Residual current monitoring
devices (RCM) 5SV8
• Residual current monitoring
• Type AC and Type A
• In = 0.03 ... 30 A
• Response time 0.02 ... 10 s
• Summation current transformer
20 ... 210 mm

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Introduction
2. Introduction
When dealing with electricity, safety has top priority. Every electrician must be
particularly conscientious when safety is concerned and must apply the required
protective measures correctly. In consumer’s installations, residual current
protective devices must be given unreserved preference over alternative protective
devices.
In addition to fault protection (protection against indirect contact), RCCBs with
rated residual currents up to 30 mA also provide “additional protection” in cases
of direct contact. Fires caused by ground-fault currents can also be prevented at a
very early stage.
In many cases, the DIN VDE standards require the use of residual current protective
devices. Electricians should therefore make sure that they are fully informed about
RCCBs. In addition to information on the protective effect, an understanding of
how the devices function is also conveyed.
In order to optimally adapt the use of the devices to the requirements of the
electrical installation, the functionality of the different versions of RCCBs is
discussed and the user is given practical installation and application tips.

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3. Protection through residual current protective devices
The basic prerequisite for use of a residual current protective device in order
to “automatically disconnect the power supply” as a protective measure is that
an appropriately grounded protective conductor is connected to the system
components and equipment to be protected. Current can then pass through
a human body only when two faults occur (interruption of the PE conductor
in addition to a fault in the insulation) or when there is unintentional contact
between live parts.
3.1 Additional protection with IΔn ≤ 30 mA
(previously “Protection against direct contact”)
Additional protection is understood to mean protection which takes effect if there
is direct contact of a human body with a part normally live during operation in the
event of basic and/or fault protection failing. If a person directly touches live parts,
two series-connected resistors determine the level of the current – the internal
resistance of the person Rmand the transfer resistance of the location Rst; see
Fig. 1.

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Protection through residual current protective devices
Direct contact
IΔn≤30mA
RBRst
Rm
IM

Fig. 1: Protection against direct contact: Additional protection means measures
to protect against direct contact with an active part that is energized
during operation.
For a proper assessment of the accident risk, it must be assumed that the contact
resistance of the location is virtually zero.
The resistance of the human body depends on the current path and the contact
resistance of the skin. Measurements have shown, for example, that a current
path of hand/hand or hand/foot has a resistance of approx. 1000 . Under these
assumptions, a touch voltage of 230 V would produce a dangerous shock current
of 230 mA. Fig. 2 shows the current intensity/exposure time curves in relation to
the physiological reactions of the human body. Dangerous current intensities and
exposure times are those which reach as far as zone , as they can cause death
due to ventricular fibrillation. It also shows the tripping ranges of the residual
current protective devices with rated residual currents of 10 mA and 30 mA. The
maximum permissible tripping times according to VDE 0664-10 are also depicted.
As can be seen from the tripping curves, residual current protective devices do
not limit the intensity of the residual current but provide protection due to fast
disconnection of the power and therefore a minimal time of exposure to the
current.