What Is Gas Bonding?

Determining the CSA of main protective bond-conductor on an installation with PME eartherens

The first change has made it clear that the PEN conductor CSA must be used when determining the CSA of a main protective bonding conductor on an installation with a PME earthing system. Table 54.8 should be used to determine the CSA of a main protective bonding conductor. If parts are deemed extraneous-conductive-parts, they should be verified before a requirement to connect them to the MET is imposed.

visual inspection is the best way to determine if a part is likely to introduce Earth potential. If it is not possible to determine by visual inspection alone, then a measurement of resistance to Earth can be obtained to determine if the part is extraneous-conductive. The equation below shows the measured resistance value between the part concerned and the MET of the installation.

The designer must consider the stability of the resistance of the part throughout the installation. Once the test has been done and a value has been obtained, a calculation can be performed to determine if the resistance is low enough for the part to be considered extraneous-conductive-part with respect to the safe level of current flow. The first problem is that the test can only be done when the other installations are complete, which means it will not always be possible to determine until later stages of the project.

The installation will not be built at the design stage. The designer will have to consider both scenarios with and without protective bonding connected. The prudent option would be to install the protective bonding conductors at the first-fix stage as it is likely to be more difficult and expensive to do later.

It would involve damage to the building fabric and be required to be installed surface mounted, which would not be desirable for most clients. Even though the incoming service pipe may not be metallic or appear not to be in contact with Earth, there may be connections with Earth throughout the installation which may or may not be apparent by visual inspection. The plastic pipe that the water pipe will enter in the building may be the only one that enters the building, but the metallic pipework that will leave the building could be connected to the earthed plant.

Bonding of the CSST Gas Pipelines

When a lightning strike or power surge is nearby, the risk of fire or damage to the gas lines increases. The difference in potential between metal and gas pipe can cause damage to the gas pipe if theCSST is not properly bonded. CSST can leak gas and cause fire if it is damaged.

The equipotential state between the gas line and metallic conductor will be achieved with the help of theCSST bonding. In the event of power surge and lightning, the risk of fire or explosion from damaged gas lines is increased. The damaged gas line is shown in the figure.

A separate bonding wire is connected to the rigid gas piping before the CSST or to one of the CSST nuts. The bonding diagram is shown in the figure. The National Fuel Gas Code, International Fuel Gas Code, and Uniform Plumbing Code all provide direct bonding for theCSST gas piping systems.

Bonding ofCSST is an electrical work that should be inspected by an electrical inspector and a qualified electrical contractor. All the electrodes must be connected together. The gas piping system requires a separate system for the grounding and electrode.

Non contact voltage detectors in mobile homes

A bonding screw is on a mobile home frame. The conductors are in front of you. One goes to the telephone ground and the other goes to the electrical distribution panel box.

Click to enlarge. If the switch is on, a non contact voltage detector will light up when it comes near. The same thing can be done with metal enclosures.

If the detector lights up when the appliance is not on, then there is a danger. Outlets are often replaced in older homes without much thought. If an older home has a three-prong outlet it must have a properly connected grounding conductor be protected from injury.

Electrical failures of earthed systems

The difference in potential between exposed and extraneous parts will not cause electric shock if the earthed equipotential zone is not faulted. There is a chance that a dangerous potential may develop between the parts of non-electrical systems that are not connected to the electrical grid. If the incoming pipes are made of plastic but the pipes within the electrical installation are made of metal, the main bonding must be carried out, the bonding being applied on the customer side of any meter, main stopcock or insulating insert and of course to the metal pipes of the installation.

Vendors insist on keeping sensitive computing and communication equipment separated from the electrical service earth, which causes equipment failures. The practice poses safety risks when lightning discharges take place in the vicinity. If the incoming services are made of plastic, then there is no need for a main bonding.

If some of the services are plastic, then they must be main bonded. There is no requirement to carry out supplementary bonding in lavatories that do not have a shower. Supplementary bonding in a kitchen or washroom is not necessary.

Supplementary bonding is carried out to the bathroom's earth terminal. A supplementary bond is not sent back to the main earth. Unless they are connected to the metallic structure of the building, metal window frames are not supplementary bonded.