Plug Covers
Outlet plug covers are safety additions that help prevent accidents and injuries sustained as a result of electrical shocks from uncovered electrical outlets. Electric plug covers also protect power outlets from environmental hazards such as water splash, temperature (heat and cold) and temperature changes (freezing), and weather. Outlet plugs enhance childproofing efforts (domestically and commercially). Many plug cover designs allow electrical cords to be easily plugged and unplugged while blocking (a child’s) access to live outlets. Childproof outlet plugs are typically clear plastic or made in colors to match a décor as to be less noticeable or tempting to small fingers.
Quick links to Plug Covers Information
Advantages and Disadvantages of Electrical Outlet Plugs
There have been few if any incidents where children, manufacturer employees, or others were harmed by outlet or socket safety covers. However, before purchasing or installing outlet or socket safety plugs, ensure they have been fully tested and meet compliance standards and requirements. Failure of the product to meet regulatory design, safety, and electrical standards defeats the purpose of installing them for the main purpose of keeping children, employees, the disabled, and others safe from electric shock or electrocution.
There are International and US 2- and 3-prong safety cover standards that must be met. However, some safety covers, once installed, can only be removed using a special pin intended for that brand or type of cover. International campaigns have spoken out against these devices, basing their objections primarily on their design, lack of being fully tested, and/or how they are intended to be installed. One opinion cites that when the plastic safety cover is inserted into the socket in a certain manner, it inadvertently activates the live portion of the socket by opening the internal "shutter" portion. Some safety covers are such that if they were not designed to be removed by an earth pin, a curious child could just as easily pull it out and put it back reversed (inverted) and get a jolt.
It is also important to remember that, when traveling, there are different voltages and frequencies around the world. There are approximately fifteen electrical outlet types globally, and adapters may be necessary as well as appropriate electrical plugs and safety covers to fit the particular receptacle.
Types of Plug Covers
- Dummy Plugs
- Childproof electrical outlets for safety. They keep the inside of 2- or 3-prong NEMA 1-15R power socket outlets clean, free of dirt and dust, and intact and safe. Outlet covers provide a secure fit to protect female power outlets and should meet agency compliance and UL flammability rating. Dummy plugs may be actual plugs or caps that insert into the outlet plate holes, a self-closing cover design that slides open when the outlet is to be utilized, or a box outlet cover type that is always plugged in until the outlet needs to be used.
- The most common concept of safety covers is those that are tamper-proof to protect babies and small children from outlets that could shock them. Dummy plugs may be decorative, but all should be too big for a small child to choke on, difficult for a small child to remove, and replaced with a new safety cover when they have been removed to utilize the outlet.
- Weatherproof Plugs and Plates
- Gasketed, self-closing, used in intermittent wet or damp locations. Low profile, box-mounted weatherproof plates protect against fine particle penetration and splashing. Weatherproof plugs are made of durable, sealed material and non-corrosive plugs.
- Twist-Lock Plugs and Plates
- Intended to minimize disconnections. One-piece locking plugs, connectors, and receptacles terminate wiring for easy connection.
- Anti-Dust Caps
- Provide a secure fit to protect female DC power jacks and/or male DC power plugs from physical damage, dirt, dust, grime, and liquids. They are typically easy to install and remove.
Materials for Plug Covers
Materials commonly used to make plug socket covers include stainless steel, zinc die cast aluminum, and commercial grade thermoplastic elastomer ethyl vinyl acetate (EVA), polyethylene (PE) and polypropylene (PP) typically used for weatherproof plates. Each material is suitable for applications requiring specific environment and weather-resistant properties and safety features.
- Stainless steel is highly anti-corrosive and chemical resistant.
- Commercial grade (zinc die cast) aluminum is an industrial material that has good electrical and thermal conductivity qualities; it is highly oxidation-resistant.
- Thermoplastic elastomer (EVA) remains extremely flexible at low temperatures and is resistant to cracking.
- More common industrial thermoplastic polyethylene (PE) offers superior electrical properties, but with significantly reduced temperature resistance.
- Polypropylene (PP) uniquely offers superior bi-axial strength and cold flow and yield elongation.
- Less common natural rubber and styrene butadiene (SBR) materials are used where increased chemical resistance to substances, such as oils and hydrocarbons, are required.
Plug Cover Uses
- Low profile, box-mounted weatherproof plugs/plates are self-closing covers that are suitable where space is limited. They resist rain spray and splashing and protect against fine particle penetration.
- Twist-lock locking plugs and connectors are one-piece, interlocking plugs that minimize disconnections. Locking plugs, connectors, and receptacles terminate wiring for easy connection. They typically have an impact- and chemical-resistant nylon housings and are available in a variety of pole/wire configurations and voltage/amperage rating. Twist-lock plugs interlock when twisted, which prevents inadvertent disconnection. They are ideal for use in clean room environments.
- Standard plugs and sockets may be utilized for indoor or outdoor, industrial or commercial applications. The highest priority is safety. They are ideal for entertainment applications, such as concerts and outdoor events, theatres, and television studios.
- Watertight plugs provide maximum protection against dirt and liquids while in use, as well as easy access to contact parts during installation.
Plug Cover Applications
Industry and commercial screwless terminal connectors, plugs, and sockets save the manufacturer installation time and maintenance. Spring technology models install without screwing. They resist vibrations and heat variations. The intent is to meet safety requirements and protect those coming in contact with outlets and cords.
Electrical socket plugs (connectors and sockets) protect employees from electric shock or electrocution. Outlets must be protected from seepage of chemicals, liquids, water, weather elements, and other corrosive agents into them.
Outlet plug covers are designed to be indoor or outdoor application-specific. Plugs used in inhospitable or harsh environments are fabricated from corrosive resistant materials. Additional accessories such as cord grips, dust shields, and tamper- and weather-resistant, and easily connected (industrial-grade) one-piece grounding systems may be necessary for particular environments. Plug socket covers also become more application-specific when there is a specific need for thermal stability, temperature-resistance, or public security.
- Indoor Safety Plug Covers
- May be a smooth, non-grip design that matches most standard outlets and decor so they are not as noticeable by children. Most are specifically designed to fit into unused three-prong electrical duplex outlets. Sliding outlet cover designs automatically close. Most auto-close safety plug covers are energy-saving thermoseal gaskets that fit a single-screw outlet.
- Indoor Electric Plug Covers
- Enclose exposed electrical outlets and plugs regardless if they are in use or not. They are also installed to keep electric plugs from falling out of the outlet socket or prevent plugs from being crushed behind doors and furniture. The tamper-proof outlet plugs are large enough so a nightlight may fit inside them. They are childproof and the plastic housing is virtually unbreakable.
- Standard Grade Shrouded Locking Connectors
- Watertight locking connectors have antimicrobial additives that reduce microbial contamination such as fungi, mold, and mildew. Closure caps help prevent water from entering.
- Standard Grade Locking Connectors
- Standard grade, nylon, non-shrouded, locking connectors are chemical- and impact-resistant. They also act as an internal dust seal.
- Standard Non-Shrouded Watertight Locking Connectors
- Standard, non-shrouded, stainless steel, watertight locking connectors that include corrosion-resistant connection points and highly conductive brass terminations are well suited for industrial-grade and commercial applications. Collected dirt and debris is minimized by cone seals, which help prevent build-up at the cable entrance. Strain-relief nuts improve impact resistance.
- Specification Grade Non-Shrouded Locking Connectors
- Have nylon housing that resists chemicals and impacts. They provide an internal dust seal. Dual-LED indicators immediately identify upstream wiring errors.
- Industrial-Grade Non-Shrouded Locking Connectors
- Typically made of sturdy, rubber or thermoplastic materials that make them impact- and abrasion-resistant. Industrial-grade models include antimicrobial additives that aid inhibition of microbial growth and contamination. Industrial-grade locking connectors are typically grounded and are able to be conveniently re-wired for multiple applications.
- Marine Grade Non-Shrouded Locking Connectors
- Made of non-corrosive materials and sturdy impact-and crush-resistant ribbed nylon housing. Stainless steel shrouds protect the plug blades. Chrome-plated brass nosepieces ensure connector/device compatibility.
Standards and Specifications for Plug Covers
Manufacturer-installed outlet plugs must meet more stringent industry safety regulations. It is important the company keeps its employees that work with or around chemicals and food processing, or in marine, construction, and telecommunication industries, for example, safe. OSHA and other regulators require industry manufacturers to provide safety features to keep employees and customers safe from shocks and accidents.
Typically, plug socket covers are designed according to their specific application. NEMA (the US National Electrical Manufacturers Association) sets standards for electrical wiring devices for industry, commercial, and residential applications based on:
- Ampere (Current Rating)
- Volt (Voltage Rating)
- Wires
Outlet plugs must meet agency and compliance requirements according to the environment, location, and type of NEMA-rated receptacle they will be installed on. Electrical plug/plate cover compliance is determined by the following agencies:
- NEC (National Electrical Code - configuration and electrical rating)
- CSA Certified (Canadian Standards Association – established safety standards)
- RoHS compliant (EU Restriction of Hazardous Substances – a "lead-free" directive; specifying materials’ composition limits)
- UL listed (Underwriters Laboratories - flammability and safety ratings)
- IPAA suitability (rating weatherproof plug covers)
Accessories of Plug Covers
Lockouts / tagouts, angle adapters, protective weather boots, and stainless steel receptacle cover plates provide a variety of features including cord grips, dust shields, and tamper-resistant, weather-resistant, and easily connected industrial-grade one-piece grounding systems.
- Nylon locking plugs and wiring connectors fit into limited space and guard right-angle devices.
- Adapters reduce the need for wire bending by allowing wire to exit parallel to the electrical receptacle.
- Shields (over power conductors) prevent electromagnetic interference on audio-video equipment cords.
- Pilot lamps serve as voltage indicators.
- LED indicators that warn of an upstream faulty or wiring error.
- Fuses offer over-current protection.