My workshop electrics and which compressor?

[gasket999]

Howdo folks.

I appreciate that which compressor should i buy has been done to death, but just wanted to check my garage electric specs with some of the more knowledgable folk here - I'm aware there are a few sparks on the forum.

My garage is fed by a 10mm2 cable running from my 100amp main consumer unit in the kitchen (this cable is currently protected in the CU by a 50amp MCB) it runs approx 16m to a second, dedicated garage consumer unit which has a second set of MCBs comprising of the usual small MCB pair for lights and sockets, but I also had a third, dedicated 32amp MCB installed which feeds a single industrial 32amp socket - like this.

The big socket was fitted with the view of using larger tools in the garage - and now its time to buy my compressor. I've been trying to get second hand units to work and have decided to bite the bullet and get a big one from MM on their VAT free day this weekend. Am sick of little ones not going me enough air so am going to get the biggest I can safely run from my supply.

But how big can I go on my power supply? I understand that the power/current drops with a longer cable and mine is very long at 16m.

Ideally I'd like to invest in one of the monster tandem motor units - the se37c270nd (2x4hp) or the smaller se29d270nd (2x3hp) - these require a 30amp minimum and I'm not sure I have that given the length of the cable.

Some of the biggest 1ph single motored ones actually ask for a 40amp supply - such as the SE18C200ND.

Could anyone offer any advice? Is the current set-up advisable, would it be better to reduce some of the MCB sizes for safety and restrict myself to a smaller compressor or would I actually have the potential to increase them to offer a better supply to the garage?

Of course, any changes will be done by a certified electrician - I'd just like to know I'm asking for the right thing.

Really appreciate any advice.

 

[Robotstar5]

If it's twin & earth clipped direct you're good for 52A at 16m, handy calculator here

 

[gasket999]

Thanks guys - thats really reassuring.

It isn't clipped straight to a wall, it runs the first 10m along the kitchen wall through heavy 35x95mm plastic conduit which is screwed onto the wall. There are other cables in the conduit but these are laid out side by side, rather than bunched.

It then goes through the kitchen wall on its own and for 6m is buried 500mm under the concrete patio in 38mm black electrical polyduct.

I'll have a play with the calculator to try and educate myself before I have the conversation with the electrician.

I suppose that if I wanted anything above the current 32amps then it would mean fitting a larger MCB for the dedicated socket in the garage and fitting a wired-in connector (like a cooker) rathe than the 32a industrial socket.

 

[brightspark]

if its not going to be moved use a 45 amp double pole isolator switch if your going to pull 40 amp off it. far cheaper than a larger socket and plug

 

[gasket999]

Excellent, thank you all very much! Looks like I'm getting my dream compressor, the 2x4hp monster - bring on an ebay blasting pressure pot!

I'll print this out and pass to the electrician so that Im sure I'm asking for the right thing.

It won't be moved so is it jut a case of replacing the 32a MCB with a 45 or 50 amp MCB and then replacing the industrial 32a socket with a 45a double pole isolator switch?

 

[Wayne.]

That se37c270nd comp reqires 45amp min according to machine marts website