Soft starter

[mickfred]

Been to have a quick look at a possible job . Five pin point putting in to feed waste compactor . The nearest board it could come off is a bout a120 meters run . Took a earth loop test at board 0.55 . If I ran 10mm 5 core am in ok for volt drop and a calculated earth loop of 0.99 (could be a little lower with the armour added in ) . Ask the compactor supplyer and they want a 32 amp C type supply .my question is would a soft starter be able to pull down the inrush current enough to switch to a B type

 

[snowhead]

Waste compactors are normally hydraulic.
The pump starts off under light load then as it's compacting the load increases considerably untill the pressure switch cuts it off at a preset limit.
It's maximum current draw is when it's at the end of the compacting cycle just as it's about to reverse back to the start position.

 

[mickfred]

Waste compactors are normally hydraulic.
The pump starts off under light load then as it's compacting the load increases considerably untill the pressure switch cuts it off at a preset limit.
It's maximum current draw is when it's at the end of the compacting cycle just as it's about to reverse back to the start position.

You could have a point . I've worked on bailers before and had issues when starting up and the main pump has tripped , had to be reset and worked fine after the startup . I do see that peak in the final push but the startup on the main pump huge . The board is rccb protected I could TT it at the load end . Haven't seen the earthing setup as the dB is a submain and the mains where locked up and no one had the keys but unlike to be anything other than a TN system with a reading so low(0.55) .

 

[westward10]

If the board is rcd protected then there isn't an issue.

 

[mickfred]

If the board is rcd protected then there isn't an issue.

It feels wrong to design a circuit that will be double it's maximum earth fault . I know you will come across it from time to time and will code it as such , but I can't think of a reg that covers me for knowingly putting a cable in with a incorrect value . I know sometime after deign a circuit you come to test it and a little higher than expected but the arguments goes out the window when you have hit the max at the board and then wired in 120 meter of cable on to it . Ta for the reply

 

[westward10]

Haven't got my Regs to hand at the moment but there is a reg stating an rcd can be used for fault protection as long as it is backed up by a protective device, in your case you do so it is perfectly compliant. I assume you are fitting a socket outlet so this will require additional 30ma rcd protection so if the board rcd is 30ma then you are covered.

 

[mickfred]

Yep fitting a five pin isolator . Am in the same boat just moved house can't find any of my books , which hasn't been a issues as only done repairs in the last few months and can only find a old sixteen edition that someone gave me

 

[westward10]

I know where book is will put up a reg later unless someone beats me to it.

 

[mickfred]

I know where book is will put up a reg later unless someone beats me to it.

Cheers Westward

 

[westward10]

Regulation 411.4.5.