20 amp circuit required for new bench grinder??

sdyck

I bought my self a new Delta 8" 5 amp grinder. The instructions state that I should be using a dedicated circuit and "the circuit should not be less than #12 wire and should be protected with a 20 Amp time lage fuse".

The plug on the grinder is a regular 15 amp style 3 bladed one, not the 20 amp plug.

I was surprised at this last requirement, is that due to peak amperage and the risk of blowing a fuse, or could it be a problem when grinding something big and the motor is under load.

Is their really a risk using a regular 15 amp circuit with 14 guage wire?

Thanks.

NolaTigaBait

you won't have a problem with that

sdyck

Thanks, couldn't imagine why they'd make that suggestion unless there was a lot more running on the circuit, which won't happen in my little home shop.

The startup amperage couldn't be 3 times the 5 amp rating could it?

InPhase277

Sure it could. It could be 6 times the 5 A rating. But circuit breakers don't trip instantaneously on overloads. They are designed for this application. You will be fine. The manufacturer is just covering their butt so no one can ever say it was their fault for anything.

sdyck

Cool, that explains what "time lag fuse" are then. Thanks

J. V.

The Chinese have a real bad habit of providing useless information (instructions) included with the product. Sometimes its easier to look at the picture to figure out how to assemble something.
Use what you have. You can always run a new circuit if needed. I doubt you will need it.

Yoyizit

At what RPM does the grinder run? You have a link to the spec's on this grinder?

Here's some generic time-lag fuse info
http://books.google.com/books?id=a98...num=4#PPA28,M1

If your motor comes up to speed in less than 1.0 second the fuse in the graph will hold if your startup current is less than ~5.3x the steady state value of current draw.
It'd be good if Delta would recommend a fuse part number and manuf. Fuses also have an interrupting current rating, and its pretty hard to specify what this needs to be for a resi. installation.

I'm wondering if there is a hidden cost of ownership for this grinder, specifically that it is very persnickety about its power source.
We had a thread on this Forum where a chopsaw tripped its breaker, but only about 1/4th of the time. If I recall, the fix was to use an extension cord with the saw.