500A 415V porcelain kit kat fuse unit with strip (heavy) — rewireable carrier and base with bolted terminal strips, for main incomers and LT feeders.
- Heavy-duty porcelain fuse unit rated 500A, 415 V — carrier and base.
- With strip: flat terminal strips at both ends of the base, with bolt, nut and washers, for cable lugs or busbar links.
- Twin clip contacts in the base grip the blade contacts of the carrier.
- Carrier embossed 500A AC and 415/500 V, with a moulded handle for pulling it out.
- Rewireable: the carrier takes fuse wire of the size specified for its rating.
- Porcelain (ceramic) base and carrier — non-combustible and heat-resistant, the traditional material for fuse units.
- Single pole — use one unit in each phase of a three-phase supply.
The largest unit in our porcelain kit kat range: a 500A, 415 V fuse carrier and base for main incomers and LT feeders in commercial and industrial buildings. The base is fixed in the panel and wired through bolted terminal strips at each end; the carrier holds the fuse wire and plugs into twin clip contacts in the base.
When the current is too high, the fuse wire melts and breaks that phase. Switch off the upstream supply before pulling the carrier, refit fuse wire of the size specified for the rating and push it back. Never fit thicker wire or bridge the carrier — the fuse wire is the protection.
Each unit protects one conductor, so a three-phase feeder needs three units, with the neutral on a link. For smaller feeders, see our 300A unit with strip and the 32A to 200A handle type units.
Where to use it
- Main incoming supply of factories, commercial complexes and apartment blocks.
- LT feeders, busbar chambers and switchboard panels.
- Replacing worn or cracked 500A units in existing panels.
How to install
- Switch off and isolate the upstream supply, and confirm the circuit is dead.
- Fix the base firmly in the panel through its fixing hole.
- Bolt crimped cable lugs or busbar links to the terminal strips at each end and tighten the nuts firmly.
- Fit the specified fuse wire in the carrier, tighten its screws and push the carrier fully into the base contacts.
Electrical work should be done by a licensed electrician. Never pull out or push in a fuse carrier on load — switch off the supply first.
Frequently asked questions
- What does "with strip" mean?
- The base has flat terminal strips at both ends with a bolt, nut and washers, so heavy cables with crimped lugs, or busbar links, can be bolted on directly.
- How many units do I need for a three-phase supply?
- Three — one in each phase. Each unit is single pole; the neutral goes through a link, never a fuse.
- What fuse wire does a 500A unit take?
- The size specified for the rating — check the marking on the carrier and follow the rating chart of the fuse wire you buy. Never use thicker wire or a solid link to stop it blowing.
- Can I pull out the carrier with the supply on?
- No. Switch off the main switch or upstream isolator first — pulling a carrier on load can draw an arc that burns the contacts and the hand holding it.
- Fuse unit or circuit breaker for a main incomer?
- A rewireable fuse is simple and economical but has to be refitted after it blows. A circuit breaker can be reset after a trip. Your electrical contractor will choose based on the installation and the supply requirements.
- 300A or 500A — which one do I need?
- Choose by the maximum current of the feeder and the cable size. The 500A heavy unit is for the larger incomers; the fuse wire fitted must never exceed what the cable can carry.
Buy 500A porcelain kit kat fuse units online from Electric Market, Chennai. For panel builders, contractors and bulk orders, contact us for a quote.