Best way to connect up air compressor

[Tbob27]

Hi,

I'm looking for some guidance from more experienced hands. Have a friend who just bought a 2.2kw air compressor which is obviously blowing the fuse in the plug due to the start-up current. Manufacturers information suggests a 30a single phase motor DOL for the power rating whilst the person who sold it said it needs a 15a fused spur.

The compressor won't be installed on its own circuit with a type c circuit breaker so wondering what the best route to take given a fused spur off the ring is limited to 13a also? Someone suggested an unfused spur to a 16a single phase 2P+E connector and plug like you see at caravan parks which could cope with the start up current but any guidance much appreciated.

 

[Avo Mk8]

Try a 13A time delay (slow blow) fuse in the plug ? ?
PS not the reliable solution!

 

[telectrix]

you could fit a 16A type C MCB in the ring, in an enclosure ,instead of a 13A FCU. then hard wire the compressor into that.

 

[Tbob27]

you could fit a 16A type C MCB in the ring, in an enclosure ,instead of a 13A FCU. then hard wire the compressor into that.

Thanks - any ideas where to source an appropriate enclosure?

 

[Yozza19]

Thanks - any ideas where to source an appropriate enclosure?

Fit a interlocked socket 16a you can get them with room to fit a mcb or rcd on din rail in the same enclosure quite a few companies do them ilme ,Garo ect

 

[Darkwood]

A little confused here, you say the manufacturer suggest fitting a DOL starter, doesn't this compressor already contain its own integral control?... or am I getting it wrong, a 2.2 kw single phase would have the effective inrush of a 5.5 to 7.5 kw 3ph so yes a 30amp front end type c would be recommended although you could use a permanent 16amp connection.

 

[pc1966]

The Hager commercial catalogue (I happen to have to hand) has 2.2kW DOL single phase protection as 50A C/D MCB, or 40A fuse. Pretty brutal!

 

[pc1966]

Page 112 of this:

https://assets.sc.hager.com/uk/-/media/project/hagerdeep/united-kingdom/hager/b2b/products/catalogues-and-brochures/pdf_brochures-and-docs/product-catalogues/2021/hager-commercial-distribution-catalogue.pdf?la=en-gb

 

[Darkwood]

I agree but he sort manufacturers guidance which usually refines the worst case scenario those charts are based on. The higher the mcb the more problematic complying with ELI which makes advice difficult without having more info.

 

[pc1966]

I agree but he sort manufacturers guidance which usually refines the worst case scenario those charts are based on.

Indeed, the figures mentioned above are more in line with my expectations. The Hager DOL values seem a bit OTT.

 

[Darkwood]

I do tend to follow those charts unless the loads are high inertia then your on a whole new level of design.

 

[pc1966]

My own experience is mostly small motors (<= 1kW) under electronic servo control, there the protection is more about stopping fires if/when the electronics fail.

 

[Darkwood]

I tend to cap at 39kw but that's just because of the industries I serve and tend to be drive controlled so minimal concerns of massive inrush.

 

[Lucien Nunes]

Try a 13A time delay (slow blow) fuse in the plug ? ?

I know this was said tongue-in-cheek but for those not familiar with fuse specs, normal 'slow-blow' cartridge fuses will not have the breaking capacity (nor will they correctly fit a 13A plug) and must not be used for this application.

 

[Tbob27]

This is a link to the manufacturers instructions if it helps from an info perspective

https://www.mark1hire.co.uk/wp-content/uploads/2018/07/electric_air_compressors.pdf