earth wire rating

[Boomer182]

i have a machine which consists of a 500mA fuse and i am using 0.5mm 11 amp rated earth wire. the boys at work tell me it should be 4mm but i thought thats ridiculous. is 0.5mm enough?

 

[jsummerfield]

Forget about the equipment fuse, instead consider the power source. In most residential and many industrial applications using 120 Vac 60 Hz systems the circuit breaker is at least 15-amperes. The safety protection must consider the source. Is this outdoors? Permanently mounted equipment outdoors may be exposed to lightning, etc. There is likely a grounding section in your applicable electrical codes to review these issues. In the US, we use the National Electrical Code; article 250 covers grounding.

John

 

[itsmoked]

0.5mm is the absolute minimum wire diameter for running 500mA. That is if you are only running that wire a meter or so.

4mm makes no sense.. that is about 6AWG or 37Amp rating.

Depending on what you are doing industrial wiring often has limits like "nothing less than 16AWG" This is for mechanical strength and to allow any electrician to have the required tools at hand.

 

[ScottyUK]

In the UK 4.0mm² is the minimum supplementary bonding conductor if mechanical protection is not provided. Are you considering the machine's internal wiring, or installation wiring?


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One day my ship will come in.
But with my luck, I'll be at the airport!

 

[itsmoked]

He didn't say 4.0mm2 he said 4mm, a length!! I thought he was talking diameters... gesh.

Teach me to deal with metric nonsense.

 

[Boomer182]

this is the machines internal wiring.
the fuse would blow well before 11 amps. i am going to upgrade the wire to maybe a 14 amp 0.75mm wire.
would i require earth ratings exceeding this and why?
Surely the earth only has to be rated enough to blow the inlet fuse?

 

[Boomer182]

i've got a bloke at work thinks 1mm 17 amp rated is not enough hes talking bout 4mm!