The earth pit cover is the cheapest part of an earthing system and the one most often skipped. Without it, the pit fills with soil and rubbish, the joint between electrode and conductor corrodes, people trip over it, and the next time someone needs to test it, they have to dig. A proper cover protects the connection and keeps the pit ready for testing.
What a good cover does
- Keeps soil, water and rubbish away from the electrode connection.
- Takes the load of whatever passes over it, whether people or vehicles.
- Opens easily for inspection and testing.
- Marks the location of the pit so it is not lost or built over.
Cast iron covers
Our cast iron pit covers, in 12″, 18″ and 24″ sizes, are heavy and strong. They suit driveways, factory floors and other places with vehicle or heavy foot traffic, where strength matters more than weight. The recessed slots let you lift them with a bar at testing time.
FRP covers
Our FRP pit cover, 450 × 450 mm and rated for 5 tonnes, is made of fibre-reinforced plastic. It is strong enough for parking areas and plant yards, yet lighter than cast iron. It does not rust, and because it does not conduct electricity, it adds a measure of safety around electrical installations.
Pit covers with chamber
Our pit cover comes with its own moulded chamber body, in 6″, 10″ and 12″ sizes. The chamber forms a neat inspection pit around the electrode top without any masonry work, and the cover is light enough for one person to lift. It suits homes, offices, rooftops and other light-traffic areas.
Comparing the options
| Cast iron | FRP (5 ton) | Cover with chamber | |
|---|---|---|---|
| Strength | Highest | High | Light duty |
| Weight | Heavy | Moderate | Light |
| Rust | Can rust if not coated | Does not rust | Does not rust |
| Conducts electricity | Yes | No | No |
| Chamber included | No, built on site | No, built on site | Yes |
| Typical place | Driveways, factory floors | Parking areas, plant yards | Homes, offices, rooftops |
How to choose
- Will vehicles pass over it? Choose cast iron or the 5 ton FRP cover.
- Is it near live equipment or in a damp, corrosive area? FRP avoids rust and does not conduct.
- Is it a home, office or rooftop pit with no vehicle traffic? A pit cover with chamber is quick to fit and tidy.
- Does the specification name a type? Follow it.
Fitting tips
- Set the cover flush with the finished ground or floor, so it is not a trip hazard and wheels roll over it.
- Leave enough room inside the chamber to reach the test joint with a spanner and tester leads.
- Number each cover and mark it on the site drawing. Our earlier guide on testing earth resistance explains why records matter.
Frequently asked questions
What size of pit cover do I need?
Large enough to reach the electrode top and the test joint comfortably with tools and tester leads. Our cast iron covers come in 12″, 18″ and 24″ sizes, and pit covers with chamber in 6″, 10″ and 12″.
Can an FRP pit cover take vehicles?
Our FRP pit cover is rated for 5 tonnes, which suits parking areas and plant yards. For heavier traffic, discuss the loads with us before choosing.
Should pit covers be labelled?
Yes. A number on each cover, matching the site drawing, makes testing and fault-finding much quicker, especially on sites with many pits.
Need covers for a project? Tell us the number, location and traffic, and we will suggest the right type and size.