Electrocution - Are Your Welders Safe?

Electrocution – Are Your Welders Safe?

The risk of electrocution is one of the most serious risks that welders face. But we believe that it can be greatly reduced through a combination of simple steps.

Health and Human Services, May 1998). Yes, you read that right, it’s totally avoidable.

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Examples of unsafe actions

he first step is the easiest yet the most

mA (or one Amp) through the chest.(Reference:

crucial - understanding the risks and the

Electrical Hazards Can Be Reduced in Agricultural

ways to prevent them. The extent of the

Welding, Jim Galloway, October 24, 2019)

injuries received when electrocuted depends on the current’s type (AC or DC), current’s magnitude (measured in Amps), the pathway of the current through the body, and the duration of current flow through the body (event). For example, only a small amount of current flow, about 5/1000 of an Amp (or five mA), can lead to a painful electric shock. Less than about 25 mA can cause muscles to “freeze up”, which prevents a person from being able to let go of objects. The heart and breathing may stop if too much current passes through the chest. Death is very likely with any current flow of less than 1,000

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What causes electrocution?

Quite simply, all major safety incidents involving electrocution can be attributed to either unsafe actions or conditions. Based on a study conducted

by NIOSH in America, the majority of the 224 occupational electrocution incidents investigated could have been prevented through compliance with existing OSHA, NEC, and NESC regulations; and/or the use of adequate personal protective equipment (PPE) (Reference: Worker Deaths by Electrocution, A Summary of NIOSH Surveillance and Investigative Findings, U.S. Department of

• • •

Working in wet environment - rainy weather Using worn and damaged welding equipment and accessories Improper grounding - energizing the work area can cause the welder to receive an electric shock, if they accidentally form the electrical path to complete the circuit (especially when there is no insulation in between).

(current flow). An arc welding machine with 50V and above (Reference: OSHA 1910.333, US NFPA 70E Article 130) can be more than enough to kill a person, especially in wet conditions either through body or environment. When damp, the current can flow easily through clothing or even leather gloves. (Reference case studies: Report of investigation into the electrocution of a fitter during welding repair on board Hong Kong registered vessel Suntec on 23 January 2010” and “Fatal Injury On Board Mathu Bhum At Gulf Of Martaban On 3 December 2016)

One key variable that protects people from electric shocks is the electrical resistance of human skin. However, if the skin is soaked with water or sweat or if the skin has a cut, this can critically lower the body’s resistance and allow more current to flow. Another key factor is the amount of voltage available to move the electrons

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Welding safety checklist Only purchase approved and compliant welding machines for maritime environment use with a minimum Ingress Protection of IP 23S as per IEC Standard 60529, that is suitable for outdoor environment.

Ensure all electrical supplies, including the Earth-leakage circuit breaker (ELCB), are functional and in good condition.

Using high Open Circuit Voltage (OCV) welding machines (OCV is the voltage between the terminals of a welding machine that is switched on but not in use i.e. no Arc) without a Voltage Reduction Device (VRD) Using AC welders and operating welding machines beyond its ampere or duty cycle ratings are especially dangerous, as they can cause overheating which results in premature deterioration of insulation and higher risk of electrical shock.

Consideration should also be given to the fact that actual welding currents may be higher than shown by indicators on the machines if welding is done with short leads or low arc voltages.

Particularly high over-currents can occur when using general purpose welding machines for low arc voltage processes such as gas tungsten arc welding (GTAW/TIG Welding).

Knowledge is power To be able to eliminate the risks of unsafe actions and conditions, welders and fitters definitely need to be educated on best practices. It is therefore essential that all welders and fitters receive hazard awareness training so that they will be able to identify existing and potential hazards present in their workplace and understand the severity of the injuries associated with each hazard. Once these hazards are identified, employers should take immediate control.

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There is still a big gap and room for improvements on the safety standards and regulations as well as enforcement with regards to electrocution risks during shipboard welding operations.

Chris Teoh Global Product Marketing Manager Welding and Tools Solution

Only use DC welding power sources with an OCVmax of below 70 volts DC and ensure that they are fitted with Voltage Reduction Device (VRD) technology, to further reduce the OCVmax to a safer level.

Always conduct pre-inspection checks to ensure that the welding machines and accessories are well-maintained.

Repair or replace damaged parts before further use.

Avoid working in wet environment as a person’s perspiration can lower the body’s resistance to electrical shock.

Place the return clamp and cable as close to where welding takes place as possible. Remember that there is as much current running through the return cable as through the welding cables.

Wear dry, insulated, and well-maintained protective clothing and leather gloves, changing as necessary to keep dry.

Wear rubber-soled shoes or stand on a dry, insulated mat to protect yourself from the work piece and return cable.

Use fully insulated electrode holders and welding cables. Do not use worn, damaged, undersized or poorly spliced cables.

Do not wrap cables that are carrying current around your body. Avoid touching an energized electrode with your bare hands and avoid coming into contact with return cables.

Turn off all equipment when not in use.

Service, maintain, and inspect welding machines and accessories regularly.

Having identified the risks, let’s take a look at the regulations which if followed, can, and will, prevent accidents.

Keeping compliant The Regulations Existing regulations in the Americas and the Occupational Safety and Health Administration (OSHA) address electrical safety in Subpart S 29 CFR 1910.302 through 1910.399 of the General Industry Safety and Health Standards. The standards contain requirements that apply to all electrical installations and utilization equipment, regardless of when they were designed or installed.

Subpart K of 29 CFR 1926.402 through 1926.408 of the OSHA construction safety and health standards contain installation safety requirements for electrical equipment and installations used to provide electric power and light at the jobsite.

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These sections apply to both temporary and permanent installations used on the jobsite.

Additionally, the National Electrical Code (NEC) and the National Electrical Safety Code (NESC) comprehensively address electrical safety regulations. NIOSH recommendations focusing on prevention are included in its Technical Document: Worker Deaths by Electrocution, A Summary of NIOSH Surveillance and Investigative Findings.

For the maritime industry, the guiding safety directives with regards to welding machines are: i. Code of Safe Working Practices for Merchant Seafarers (COSWP, UK)-amendment 3 October 2018 specifies that: • 24.6.1 & 24.6.2 For rectifiers and inverters delivering DC: Max 70 V DC & For transformers delivering AC Max 25 V AC • 24.6.4 Earth return clamp must be connected as closely as possible to welding piece and not directly to the vessel’s hull ii. Maritime and Port Authority (MPA) of Singapore via Shipping Circular No. 5 of 2018 states that: • Ship owners, managers and operators of Singapore registered ships are recommended to fit the Voltage Limiting

Device (VLD) or Low Voltage Shock Preventer (LVSP) on the shipboard’s AC electric arc welding equipment and the recommendation to use VLD or LVSP is to be included in the company’s safety management system (SMS).

The right tools for the job Another important step towards dramatically reducing the risk of electrocution is ensuring that welders or fitters have a voltage reduction device (VRD) inbuilt into the welding machines they are working with.

A lot of new welding machines and some older units have an open circuit voltage in excess of 105 volts DC or 85 volts AC. This voltage may be quite safe in normal (dry) conditions but in reality, over 90% of onboard environment do not have these normal conditions e.g. (damp or wet, caustic, salty, working at height or in a confined space). An electric shock in these conditions can and has been proven to be fatal.

When a VRD is fitted to a welding machine, it reduces the maximum unloaded open circuit voltage across the output terminals of the

welder to a safe lower voltage, especially for AC welders. Developed countries such as Canada and Australia have introduced and implemented the more stringent requirements for VRD in welding machines e.g.: • Canadian CSA Standard for Welding Safety (CSA W117.2:19) require a Voltage Reduction device (VRD) for welding under high risk conditions.

• Australian Standards 1674.2 2003 states that all welding machine operated must be fitted with Voltage Reduction Device (VRD) and the open circuit voltage (OCV) must be 35 V DC or 25 V AC and below.

Meanwhile, European countries have adopted the EN 60974-1/5 for Arc Welding Appliance where welding machines with the ‘S’ mark indicates that the equipment is suitable for use in areas with increased electric shock hazard. This is particularly important when working in potentially wet, humid and cramped locations. Besides that, the welding machines should be rated a minimum IP 23 S for outdoor use e.g. at the weather deck. This is in accordance to the IEC Standard 60529: Ingress Protection Code.

An arc welding machine with 50V and above can be more than enough to kill a person, especially in wet conditions either through body or environment. When damp, clothing or even leather gloves.

Chris Teoh Global Product Marketing Manager Welding and Tools Solution

The next step While these best practices, recommendations, and current regulations are in place, improvements can still be made to reduce electrocution risks that occur during shipboard welding operations.

This is especially crucial when it comes to the adoption of VRD technology in DC welding machines, where welding is used in maintenance and repair works onboard.

A task force comprising of subject matter experts could be a positive step to actively enforce regulations and safety standards, to reduce electrocution risks and avoid tragic incidents like the Mathu Bhum case.

Chris Teoh Global Product Marketing Manager- Welding and Tools Solution Connect with our experts on LinkedIn 5

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