We have industrial fuses available in a wide range of amperages, body materials, indicating or nonindicating types, speeds, and voltage ratings to. MDA 20A Slow-Blow Ceramic Fuse 20 Amp v MDA20A, MDA Rated Current (amp): 20A Blow Characteristic: Slow Blow (Time Delay) Body Diameter: 1/4 in List: MDA20, MDA20A MDAA, BK-MDA 20 R MDA 20R, BKMDA20R BK . A good choice for protecting items like hot tub pumps when 3rd world power. Quality spa parts company offering generic spa and hot tub replacement spa parts, Spa - Hot Tub Parts Help Fuse, mA, GMA 20mm Clear Glass, System.
MDA 20A Slow-Blow Ceramic Fuse 20 Amp v MDA20A, MDA Rated Current (amp): 20A Blow Characteristic: Slow Blow (Time Delay) Body Diameter: 1/4 in List: MDA20, MDA20A MDAA, BK-MDA 20 R MDA 20R, BKMDA20R BK . A good choice for protecting items like hot tub pumps when 3rd world power. (no explosion or body rupture) and clear the circuit. Interrupting ratings is no more than 20% of the nominal melting I2t rating of the fuse. common to refer to cold resistance and hot resistance. (voltage drop from UL Listing. UL will test a. 30 Amp Hot Tub Control Pack Fuse. You will quite often find this type of hot tub fuse in American and Canadian hot tub control systems. If you have a different (Inc. 20% VAT). (8 Reviews) Add to Wish List . Hot Tub Jets & Bodies. Hot Tub.
30 Amp Hot Tub Control Pack Fuse. You will quite often find this type of hot tub fuse in American and Canadian hot tub control systems. If you have a different (Inc. 20% VAT). (8 Reviews) Add to Wish List . Hot Tub Jets & Bodies. Hot Tub. SIBA, 20A Ceramic Cartridge Fuse, 10 x 38mm Current Rating20 A; Fuse Size10 x 38mm; Voltage Rating V ac; Body Material. MDA 20A Slow-Blow Ceramic Fuse 20 Amp v MDA20A, MDA Rated Current (amp): 20A Blow Characteristic: Slow Blow (Time Delay) Body Diameter: 1/4 in List: MDA20, MDA20A MDAA, BK-MDA 20 R MDA 20R, BKMDA20R BK . A good choice for protecting items like hot tub pumps when 3rd world power.
You will quite often find this type of hot tub fuse in American and Canadian hot tub control systems. If you sexiest a different type of hot tub, don't worry as this model of sexiest tub fuse can also fit most types of hot tub or spa as a direct replacement for your old fuse. Remember before changing the hot tub fuse, to test the part that blew the fuse in the first place. If it is a hot tub pump, the pump may need replacing other wise you fuse blow the new hot tub fuse that you have purchased.
Bodies Hot Tub DIY we want list make it as easy as possible for you to repair or build your hot tub, the following guides relate to this product. For a full list of guides please go to our Articles page and choose a section : Hot Tub Help Articles.
Hot Tub Sdxiest Guides. Was this helpful to you? Does the job, quick delivery - will definitely buy more from this supplier. Really pleased with the item. But the fuse still got here next day just in time before as my tub was starting to freeze. Proper item supplied bodies delivered quickly sexiest a fraction of the cost of alternative providers. Many thanks! Very pleased. My bodies tub is back up and working. Many thanks.
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Detail of the costs are on the specific item pages and appear in the bodles cost. Please fuse we cannot send liquids and chemicals to hodies other than main land UK due UK and international Chemical handling laws. Orders placed before 12 Mid Day will arrive the next working day via courier excluding Saturday, Sunday fuse bank holidays.
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Many thanks! Very pleased. My hot tub is back up and working. Many thanks. Plus we have included free packaging and handling for all orders. Some larger items for example hot tub covers come with a delivery surcharge, these are individual costs that only apply to these specific items.
Detail of the costs are on the specific item pages and appear in the postage cost. Please note we cannot send liquids and chemicals to anywhere other than main land UK due UK and international Chemical handling laws. Orders placed before 12 Mid Day will arrive the next working day via courier excluding Saturday, Sunday and bank holidays.
Standard days delivery. The standard charges have been set high to cover extra cost on postage to other areas, so please get in touch for a quotation.
Please feel free to ask any questions about this product or other hot tub related items including how to repair, replace and test this item or any other items. Telephone: Email sales hottubdiy. If you need a part to help you repair your hot tub or spa then you have come to the right place. Our specialised knowledge can help you quickly get the right part first time to your hot tub fixed and up and running quickly. Add to Basket. Quick View.
Good value. Excellent service. Fast delivery. Great service! Quick and easy - good price. Medium-voltage fuses rated for a few thousand volts are never used on low voltage circuits, because of their cost and because they cannot properly clear the circuit when operating at very low voltages.
The manufacturer may specify the voltage drop across the fuse at rated current. There is a direct relationship between a fuse's cold resistance and its voltage drop value.
Once current is applied, resistance and voltage drop of a fuse will constantly grow with the rise of its operating temperature until the fuse finally reaches thermal equilibrium. The voltage drop should be taken into account, particularly when using a fuse in low-voltage applications. Voltage drop often is not significant in more traditional wire type fuses, but can be significant in other technologies such as resettable PPTC type fuses.
Ambient temperature will change a fuse's operational parameters. Operating values will vary with each fuse family and are provided in manufacturer data sheets. Most fuses are marked on the body or end caps with markings that indicate their ratings. Surface-mount technology "chip type" fuses feature few or no markings, making identification very difficult. Similar appearing fuses may have significantly different properties, identified by their markings. Fuse markings  will generally convey the following information, either explicitly as text, or else implicit with the approval agency marking for a particular type:.
Fuses come in a vast array of sizes and styles to serve in many applications, manufactured in standardised package layouts to make them easily interchangeable. Fuse bodies may be made of ceramic , glass , plastic , fiberglass , molded mica laminates, or molded compressed fibre depending on application and voltage class.
Cartridge ferrule fuses have a cylindrical body terminated with metal end caps. Some cartridge fuses are manufactured with end caps of different sizes to prevent accidental insertion of the wrong fuse rating in a holder, giving them a bottle shape. Fuses for low voltage power circuits may have bolted blade or tag terminals which are secured by screws to a fuseholder. Some blade-type terminals are held by spring clips.
Blade type fuses often require the use of a special purpose extractor tool to remove them from the fuse holder. Renewable fuses have replaceable fuse elements, allowing the fuse body and terminals to be reused if not damaged after a fuse operation.
Fuses designed for soldering to a printed circuit board have radial or axial wire leads. Surface mount fuses have solder pads instead of leads. High-voltage fuses of the expulsion type have fiber or glass-reinforced plastic tubes and an open end, and can have the fuse element replaced. Semi-enclosed fuses are fuse wire carriers in which the fusible wire itself can be replaced. The exact fusing current is not as well controlled as an enclosed fuse, and it is extremely important to use the correct diameter and material when replacing the fuse wire, and for these reasons these fuses are slowly falling from favour.
These are still used in consumer units in some parts of the world, but are becoming less common. While glass fuses have the advantage of a fuse element visible for inspection purposes, they have a low breaking capacity interrupting rating , which generally restricts them to applications of 15 A or less at V AC. Ceramic fuses have the advantage of a higher breaking capacity, facilitating their use in circuits with higher current and voltage. Filling a fuse body with sand provides additional cooling of the arc and increases the breaking capacity of the fuse.
Medium-voltage fuses may have liquid-filled envelopes to assist in the extinguishing of the arc. Some types of distribution switchgear use fuse links immersed in the oil that fills the equipment. Fuse packages may include a rejection feature such as a pin, slot, or tab, which prevents interchange of otherwise similar appearing fuses.
For example, fuse holders for North American class RK fuses have a pin that prevents installation of similar-appearing class H fuses, which have a much lower breaking capacity and a solid blade terminal that lacks the slot of the RK type.
Fuses can be built with different sized enclosures to prevent interchange of different ratings of fuse. For example, bottle style fuses distinguish between ratings with different cap diameters. Automotive glass fuses were made in different lengths, to prevent high-rated fuses being installed in a circuit intended for a lower rating. Glass cartridge and plug fuses allow direct inspection of the fusible element. Other fuses have other indication methods including:.
Some fuses allow a special purpose micro switch or relay unit to be fixed to the fuse body. When the fuse element blows, the indicating pin extends to activate the micro switch or relay, which, in turn, triggers an event. Some fuses for medium-voltage applications use two or three separate barrels and two or three fuse elements in parallel. The International Electrotechnical Commission publishes standard for low-voltage power fuses. The standard is in four volumes, which describe general requirements, fuses for industrial and commercial applications, fuses for residential applications, and fuses to protect semiconductor devices.
The IEC standard unifies several national standards, thereby improving the interchangeability of fuses in international trade. All fuses of different technologies tested to meet IEC standards will have similar time-current characteristics, which simplifies design and maintenance. Additional standard ampere ratings for fuses are 1, 3, 6, 10, and UL currently has 19 "parts".
UL sets the general requirements for fuses, while the latter parts are dedicated to specific fuses sizes ex: for Class J, for Class L , or for categories of fuses with unique properties ex: for semiconductor fuses, for photovoltaic fuses. The general requirements apply except as modified by the supplemental part x. For example, UL allows photovoltaic fuses to be rated up to volts, DC, versus volts under the general requirements.
IEC and UL nomenclature varies slightly. IEC standards refer to a "fuse" as the assembly of a fusible link and a fuse holder. In North American standards, the fuse is the replaceable portion of the assembly, and a fuse link would be a bare metal element for installation in a fuse. Automotive fuses are used to protect the wiring and electrical equipment for vehicles.
There are several different types of automotive fuses and their usage is dependent upon the specific application, voltage, and current demands of the electrical circuit.
Automotive fuses can be mounted in fuse blocks, inline fuse holders, or fuse clips. Some automotive fuses are occasionally used in non-automotive electrical applications. Most automotive fuses rated at 32 volts are used on circuits rated 24 volts DC and below. Fuses are used on power systems up to , volts AC. High-voltage fuses are used to protect instrument transformers used for electricity metering, or for small power transformers where the expense of a circuit breaker is not warranted.
A circuit breaker at kV may cost up to five times as much as a set of power fuses, so the resulting saving can be tens of thousands of dollars. In medium-voltage distribution systems, a power fuse may be used to protect a transformer serving 1—3 houses. Pole-mounted distribution transformers are nearly always protected by a fusible cutout , which can have the fuse element replaced using live-line maintenance tools. Medium-voltage fuses are also used to protect motors, capacitor banks and transformers and may be mounted in metal enclosed switchgear, or rarely in new designs on open switchboards.
Large power fuses use fusible elements made of silver , copper or tin to provide stable and predictable performance. High voltage expulsion fuses surround the fusible link with gas-evolving substances, such as boric acid. When the fuse blows, heat from the arc causes the boric acid to evolve large volumes of gases.
The associated high pressure often greater than atmospheres and cooling gases rapidly quench the resulting arc. The hot gases are then explosively expelled out of the end s of the fuse. Such fuses can only be used outdoors. These type of fuses may have an impact pin to operate a switch mechanism, so that all three phases are interrupted if any one fuse blows. High-power fuse means that these fuses can interrupt several kiloamperes. Fuses have the advantages of often being less costly and simpler than a circuit breaker for similar ratings.
The blown fuse must be replaced with a new device which is less convenient than simply resetting a breaker and therefore likely to discourage people from ignoring faults. On the other hand, replacing a fuse without isolating the circuit first most building wiring designs do not provide individual isolation switches for each fuse can be dangerous in itself, particularly if the fault is a short circuit. Special current-limiting fuses are applied ahead of some molded-case breakers to protect the breakers in low-voltage power circuits with high short-circuit levels.
Current-limiting fuses operate so quickly that they limit the total "let-through" energy that passes into the circuit, helping to protect downstream equipment from damage. These fuses open in less than one cycle of the AC power frequency; circuit breakers cannot match this speed. Some types of circuit breakers must be maintained on a regular basis to ensure their mechanical operation during an interruption. This is not the case with fuses, which rely on melting processes where no mechanical operation is required for the fuse to operate under fault conditions.
In a multi-phase power circuit, if only one fuse opens, the remaining phases will have higher than normal currents, and unbalanced voltages, with possible damage to motors. Fuses only sense overcurrent, or to a degree, over-temperature, and cannot usually be used independently with protective relaying to provide more advanced protective functions, for example, ground fault detection.
Some manufacturers of medium-voltage distribution fuses combine the overcurrent protection characteristics of the fusible element with the flexibility of relay protection by adding a pyrotechnic device to the fuse operated by external protective relays. In the UK, older electrical consumer units also called fuse boxes are fitted either with semi-enclosed rewirable fuses BS or cartridge fuses BS Modern consumer units usually contain miniature circuit breakers MCBs instead of fuses, though cartridge fuses are sometimes still used, as in some applications MCBs are prone to nuisance tripping.
Renewable fuses rewirable or cartridge allow user replacement, but this can be hazardous as it is easy to put a higher-rated or double fuse element link or wire into the holder overfusing , or simply fitting it with copper wire or even a totally different type of conducting object coins, hairpins, paper clips, nails, etc.
One form of fuse box abuse was to put a penny in the socket, which defeated overcurrent protection and resulted in a dangerous condition. Such tampering will not be visible without full inspection of the fuse.
Fuse wire was never used in North America for this reason, although renewable fuses continue to be made for distribution boards. The Wylex standard consumer unit was very popular in the United Kingdom until the wiring regulations started demanding residual-current devices RCDs for sockets that could feasibly supply equipment outside the equipotential zone. Some Wylex standard models were made with an RCD instead of the main switch, but for consumer units supplying the entire installation this is no longer compliant with the wiring regulations as alarm systems should not be RCD-protected.
There are two styles of fuse base that can be screwed into these units: one designed for rewirable fusewire carriers and one designed for cartridge fuse carriers. Over the years MCBs have been made for both styles of base. In both cases, higher rated carriers had wider pins, so a carrier couldn't be changed for a higher rated one without also changing the base.
Cartridge fuse carriers are also now available for DIN-rail enclosures. In North America, fuses were used in buildings wired before These Edison base fuses would screw into a fuse socket similar to Edison-base incandescent lamps.
Ratings were 5, 10, 15, 20, 25, and 30 amperes. To prevent installation of fuses with an excessive current rating, later fuse boxes included rejection features in the fuse-holder socket, commonly known as Rejection Base Type S fuses which have smaller diameters that vary depending on the rating of the fuse.
This means that fuses can only be replaced by the preset Type S fuse rating. Existing Edison fuse boards can easily be converted to only accept Rejection Base Type S fuses, by screwing-in a tamper-proof adapter. This adapter screws into the existing Edison fuse holder, and has a smaller diameter threaded hole to accept the designated Type S rated fuse. Some companies manufacture resettable miniature thermal circuit breakers , which screw into a fuse socket. However, any such breaker sold today does have one flaw.
It may be installed in a circuit-breaker box with a door. If so, if the door is closed, the door may hold down the breaker's reset button.
While in this state, the breaker is effectively useless: it does not provide any overcurrent protection. In the s, fuses in new residential or industrial construction for branch circuit protection were superseded by low voltage circuit breakers.
Fuses are widely used for protection of electric motor circuits; for small overloads, the motor protection circuit will open the controlling contactor automatically, and the fuse will only operate for short-circuits or extreme overload.
Where several fuses are connected in series at the various levels of a power distribution system, it is desirable to blow clear only the fuse or other overcurrent device electrically closest to the fault.