Continuity measurements between metal enclosures (mass) and earth (ground) of electrical equipment
Note: During my professional activities as electrical engineer (40 years) I verified always the electrical continuity of bonding and grounding conductors (PE, protective earth).
Note added at 15 hrs (2015-01-19 11:49:33 GMT)
Unfortunately no source text up to now, only some interpretations:
„It involves the controle electrique des taip off box suivant les prescriptions du RGIE (General Regulations on Electrical Installations“
„patchy one-page text with different components of an inspection (discharges and arcs, energy storage, loss of voltage....).”
“It is one page for an entity to tell a customer (I expect) some of the components of an inspection they entity is poised to undertake (if the customer accepts). I just wondered if there were a cover-all, non-committal way of translating masses. It will then be up to the entity to be more specific, when they flesh out their tender proposal (I am guessing this is what they are leading up to). The text is not instructing anybody do to anything, so nobody is at risk. Just my backside. That is the full sentence, Robin.“
“Just the techncially precise ehadword term, and the 'dumbed down' "more neutral" one at Asker's request — with a note to the effect that the choice depends on exact context.”
What can we deduct from this?
“taip off box” is surely “tap-off box”.
“General Regulations on Electrical Installations”; RGIE is obviously the French abbreviation of “Règlement Général sur les Installations Électriques »
“different components of an inspection” may concern the final acceptance of a house connection or installation.
“poised” looks strange in the context, unclear what it refers to.
“headword” is surely “headword”, title.
2007/0019/B Royal Decree amending Articles 105 to 113 of the General Regulations on Electrical Installations (RGIE) 11.4.2007
2007/0019/B Arrêté royal modifiant les articles 105 à 113 du Règlement Général sur les Installations Electriques (RGIE) 11.4.2007
[...] inspected the high-voltage lines according to the conditions of the AREI (Belgian General Regulation on Electrical Installations).
Nos agents spécialisés contrôlent les lignes à haute tension conformément aux prescriptions du RGIE pour le compte d'Elia.
The question was « Mesure de continuité électrique des masses du matériel électrique »
A word-by-word translation would result in “Measurement of electrical continuity of electrical equipment masses”
For tests requiring measurement of electrical continuity between end fittings or through continuous internal or externally bonded wires, use an ohmmeter with sufficient accuracy to determine the resistance to within +/- 10%.
“alternatively, specific down conductors embedded in the structure, with electrical continuity ensured by welding or by suitable mechanical connection, and connected to reinforced steel bars for the equalization of potential”;
According to the NBR 5419/2005, "measurements should be performed between the top and the bottom of some pillars and between the reinforcement steel bars of different pillars, to ascertain the continuity through beams and slabs”. In relation to the measured values, the Brazilian standard indicates that “these measures should result in resistance below 1 Ω”.
According to the IEC , “…the electrical continuity of the reinforcing bars shall be determined by electrical testing between the uppermost part and ground level. The overall electrical resistance should not be greater than 0.2 _, measured using test equipment suitable for this purpose.” Thus, the permissible values for the tests are different, but the points of measurement are also different.
250/500/1000 V CAT IV Insulation & Continuity Tester
• Insulation testing up to 1000 V and 20 GΩ
• Patented analog arc and dual digital display
• CAT IV 600 V rating
• TRMS & DC Voltage measurement
• Continuity testing at 200 mA or 20 mA down to 0.01
IN SERVICE INSPECTION AND
TESTING OF ELECTRICAL EQUIPMENT
THE EARTH CONTINUITY TEST
By John Ware
Electrical equipment must be maintained so as to prevent danger. The IEE’s Code of Practice for In-Service Inspection and Testing recommends that maintenance of electrical equipment is carried out in four stages: Visual inspection, Test to verify earth continuity, Test to verify insulation, and Functional test. In this article we will discuss Class I equipment and the earth continuity test.
The earth continuity test can only be applied to Class I equipment, extension cables or cords. Class I equipment is equipment that relies on a connection with earth for its safety (protective earthing) and/or needs a connection with earth for it to work (functional earthing).
Where protective earthing is provided, as is likely for many household appliances, tools and luminaires, the earth continuity test is vital as the safety of the appliance depends upon an ongoing reliable connection with the means of earthing of the fixed electrical installation.
The earth continuity test
One of the following two tests should be carried out.
(i) A continuity measurement with a test current up to a maximum of the order of 25 A (The hard test). A continuity measurement should be made with a test current not less than 1.5 times the rating of the fuse and no greater than 25 A for a period of between 5 and 20 seconds.
(ii) A continuity measurement with a short-circuit test current in the range 20 to 200 mA. (The soft test)
Which test to perform?
Test (i) is the preferred test. It must be remembered that some electrical test equipment can apply tests which are inappropriate and may even damage equipment containing electronic circuits, possibly causing degradation to safety. If there is a possibility that damage may result due to the test current which can be up to a maximum of 25 A when Test (i) is used then Test (ii) should be performed. Metal-cased business equipment, such as a computer mainframe, is normally tested by using Test (ii) whereas an appliance such as an electric fire, washing machine or fridge normally should be tested using Test (i).
Performing the test
The continuity test should be made between:
_ All accessible earthed metal parts of the equipment (exposed-conductive-parts) and the earth pin of the
plug for a plug-in appliance or _ The earthing terminal of the fixed wiring supply for equipment which is permanently-connected such as a hand drier.
The measured values
The measured resistance should not exceed the values given in Table 1. In the event that a higher resistance is measured, the person testing the equipment will have to ascertain the reason for the elevated reading, decide if it can or should be corrected and, if not, decide if the appliance is safe for continued use.
For appliances (0.1 + R) ohm where R is the resistance with a supply cord of the protective conductor of the supply cord
For appliances without a supply cord 0.1 ohm
Table 1: Continuity readings
Earth Continuity Tester
Resistance value: 0.001 to 1.200 Ω
Test Current: 3 to 30 A AC
The TOS6200 tester is designed to perform the earth continuity tests required for class-I devices by safety standards such as IEC, EN, VDE, BS, UL, JIS, and the Electrical Appliance and Material Safety Low (Japan).
Equipped with a new high-efficiency power supply, it is compact and lightweight, about half the size and weight of our conventional products, while achieving a large output of 150 VA
I conducted always Test 1 (25 A, 0.1 Ω) acc. EN 60335-1 (series production test).
Note: fixed installations or repaired appliances are tested against different standards, which requires different values.
NF EN 61557-4 Juin 2007
Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1 500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 4 : résistance de conducteurs de terre et d'équipotentialité
BS EN 61557-4:1997, IEC 61557-4:1997
Electrical safety in low voltage distribution systems up to 1000 V a.c. and 1500 V d.c. Equipment for testing, measuring ormonitoring of protective measures. Resistance of earth connection and equipotential bonding
Still some definitions:
IEV ref 714-11-17
check made of a connection to verify that a transmission path exists
contrôle de continuité
vérification d'une chaîne de connexion pour s'assurer de l'existence d'un trajet de transmission
Domain note dispositifs électriques et magnétiques
Definition corps conducteur dont le potentiel est pris comme référence
Reliability 3 (Reliable)
Definition the conductive body whose potential is taken as reference
Reliability 3 (Reliable)
Reliability 3 (Reliable)
Area Electrical accessories / General
IEV ref 442-01-21
exposed conductive part
a conductive part of electrical equipment, which can be touched and which is not normally live, but which can become live when basic insulation fails
Note – A conductive part of electrical equipment which can only become live through contact with an exposed-conductive-part which has become live is not considered to be an exposed-conductive-part itself.
partie conductrice d'un matériel électrique susceptible d'être touchée et qui n'est pas normalement sous tension mais peut le devenir lorsque l'isolation principale est défaillante
Note – Une partie conductrice d'un matériel électrique qui ne peut être mise sous tension que par l'intermédiaire d'une masse qui est devenue sous tension n'est pas considérée comme une masse.
| Johannes Gleim|
Local time: 05:04
Specializes in field
Native speaker of: German
PRO pts in category: 153