What size fuse do I need? (Calculating amperage)

In this video, Adam talks through the formula for calculating your amperage which will help determine the size fuse you need for your electrical installation.

Total Wattage / Voltage = Amperage

NOTE: Narva Ultima 215 L.E.D driving lights require a 40 AMP fuse

M O R E I N F O:

[leol]

Thank you that was exactly what I was wondering. Great video.

[Amcor]

"27.5 amp, we can quite easy fit a 30, maybe even a 40amp fuse" - why? How much higher can it and should it be? Why MAYBE 40 amp? Does that mean it could be running at 39.9 amps for a long period of time without anyone knowing? What are the conditions for the increase? This is not clear!

[generalharness]

Hello


The comment the fuse will protect the accessories is misleading. The fuse will only blow if there is something wrong with the circuit and it will not protect from a surge instantly. The reason for this is that a fuse is a bit of wire rated at a slightly lower amperage in a plastic shell, this means it has a delayed blow time while the wire heats up enough to melt and will only operate instantly at a massive surge (something like 10 times its rated capacity for standard ATS fuses). Until the fuse blows the components are still under the stress of the amperage going though it and the more sensitive parts can fail.


The only reason you install a non specialized fuse is to stop the circuit when a device faults until the device is repaired.


Please also note that you need a qualified sparky to do anything with 230v fuses and that a 230v fuse is different to a 12v one in how it prevents the arcing when it blows. Do NOT use a 12v fuse for a 230v appliance even if the amps are within the ratting on the fuse.

[faridbakhshian]

hi, a question . when we calculate 27.5 amps and we pick a 30 fuse or 40 fuse we are acutually letting more amps into the circuit . how it does not damage our circuit?? what is the maximum fuse amp that we can use for a safe circuit in this case?

[matthewstollar]

What amp do I need in our fuse box that is the circuit to five upstairs lights? One light is in the bathroom, another on the landing and four main lights in three bedrooms

[gaowen]

I've got a 876w light bar. What size fuse and relay should I run?

[Espiritiv]

You didn't actually tell us how to calculate the fuse size needed. You only told us how to calculate the amperage of our system