Earthing Confirmation Relay 2
Description: Earthing Confirmation Relay 2
Earthing Confirmation Relay(ECR2) is a complete solution with Measurement of two earth pit resistance which is displayed for Engineers and safety professionals at plant who work long and hard ensuring elimination of the possibility of fires of explosions in areas where flammable or combustible material are being processed, handled or stored.
This involves identifying all potential ignition sources-whether electrical, hot surfaces, mechanical sparks or naked flames. However, no matter how well the working environment has been designed, there’s one potential source of spark discharges that’s ever present in virtually every workplace and that has enough energy to ignite all common flammable or combustible liquid vapours and gases as well as many airborne dusts and loose solid materials. That energy source is “Static Electricity”, also known as “Electrostatic” or just simply “Static”.OPERATION PROCEDURE
A quick summary of the sequences of operations of the ECR-2 is as follows
- There are four terminal E1, P1, P2, E2 which complete earthing path of equipment or tanker earthing.
- E1 & E2 must be connected to earth pit (As per drg. Shows). It measure earth resistance between Earth pit 1 and Earth pit 2.
- There are two Clamp from the Earthing Relay : P1 and P2. The intrinsically safe grounding circuit of the Earthing Relay is well protected and designed to discharge static charge in several kilo-volts from Tanker or equipment to be earth.
- Probe P2 must first be clamped t the vehicle or equipment first.
- The charge on the vehicle is carried through P2 to Ground (as ‘E’ True Earth terminalof the instrument). It is essential that the instrument be properly earthed.
- After the static charge is grounded, the Probe P1 (clamp) should be connected to the vehicle (after about 2-3 seconds).
- If the vehicle is fully grounded through E1 & E2 the potential difference between the two probes P1 and P2 will be near-zero and the Relay will change state and the loading may be commenced.
- So, as per above instrument will first confirm earth pit resistance between E1 & E2 and thereafter make earthing confirmation of Vehicle or equipment through P1 & P2 clamps. In this condition if the resistance of the entire loop as between earth pit to cable or conductive pipe to vehicle or equipment is less than present factory set value as between range 0 to 12 ohms., relay will change state and loading or alarm may be commenced.
- However, in the unlikely event that the vehicle does not get fully discharged through P2 and P1 is also clamped to the vehicle, then the charge will appear on P1 also and the slow-Glow Fuse F2 in series with P2 will blow out, causing the instrument to stop functioning immediately.
- There are two protection fuses within the instrument. (F2) if intrinsic safe circuit gets damaged internally for any reason, or (F1) if there is a short in the power supply section, the corresponding fuses will blow and the Power will immediately go off.