Risk Assessment: Electromechanical Erection
Workers Affected by Works Hazards
PREVENTIVE MEASURES
Rules for acting
2ª. FORESEE ANY POSSIBLE RECHARGING:
The manipulation devices used to disconnect the installation must be ensured against any possible reconnection, preferably via a manoeuvre lockout mechanism, and a sign must be placed, whenever necessary, prohibiting the manoeuvre. In the absence of mechanical lockout, equivalent protection measures are to be adopted. When using remote-control devices, erroneous manipulation of these devices from the remote control must be impeded.
When an auxiliary power source is needed to manipulate a cut-off device, said source must be deactivated or must act on the elements of the installation in such a way that the separation between the device and the source is ensured.
This step refers to the fact that it must be possible to lockout cut-off devices in a way that impedes the manipulation or actuating of the device as a result of human or technical faults.
Lockout of the manoeuvring device may be achieved by the following means:
- Mechanical (locks, padlocks, chains, etc.).
- Electrical (fuses in the actuating circuit).
- Pneumatic (disconnecting pneumatic power sources, discharging cylinders, etc.).
- Physical (obstacles between the circuit-breaker blades).
Should lockout not be possible, the actuating control device must be signposted by means of a sign, signal or lettering warning of the danger. If it has no control-actuating element, the signposting is to be placed on the device itself or in its vicinity.
Signposting is to be the minimum protection when cut-off devices cannot be locked-out.
3ª. VERIFYING THE ABSENCE OF VOLTAGE:
The absence of voltage must be verified in all the live elements of the electrical installation in, or as close as possible to, the work area. In the case of high voltage installations, the proper functioning of the devices for verifying the absence of voltage must be checked before and after said verification.
When checking the absence of voltage in an installation, act as if it were live until the contrary is confirmed. Therefore, appropriate protective elements are to be used (insulating gloves, safety helmet, goggles or visor, insulating bench or mat, etc.) and the safety distance is to be respected, i.e. the minimum distance that must exist between the closest point to live parts and any extreme part of he worker, depending on the rated voltage.
4ª. SHORT-CIRCUITING TO GROUND DEVICES:
The parts of the installation where work is to be carried out must be short-circuited to ground.
Short-circuit to ground equipment and devices must be connected first to the earth and then to the elements to be grounded and must be visible from the work area. Should this last condition not be possible, the grounding connections must be placed as near to the work area as possible.
The conductors used for grounding and short-circuiting are to be suitable and have a sufficient cross-section for the short-circuit current of the installation where they are installed. Precautions are to be taken to ensure that the grounding conductors remain properly connected for the duration of the work.
