correct wiring for 30 amp

[harry68]

good day all

 

looking for good advise for 30 amp hook up and distribution

 

We are having a new 30 amp metre installed and will run from the metre about 30 metres to a breaker room i have made

from there i need to go underground to 3 small huts.

 

1) what type of breaker box will i need to receive the 30 amp

2) what type of box is require to slit to 3 rooms

3) the cable i run underground should it be just a single cable with 3 wires or should it be 2 separate wires that go in seperate conduct into each separate hut to there own breaker box.

 

have had several different suggestions from locals so looking for some better advise

 

Thank in advance

 

Cheers 

Harry

[AussieBob18]

Mate - find a retired ex-electrician Expat.  I hope one answers your OP.

 

[Crossy]

OK, so you are having a 30/100 meter? (100A maximum)

 

I would run 2-core 25mm2 NYY cable in a conduit underground from meter to the breaker room - Check that your local PEA office are OK with using 2-core, some seem to insist on two single core cables (both can be in the same duct). The breaker room will be your main board as far as PEA are concerned so you'll need a MEN link and ground rod there.

 

In the breaker room split the incoming to three sub mains, one for each hut. What load do you anticipate for each hut? How far from the breaker room to the huts?

 

In each hut have a small distribution board. Size will be determined by what load you are expecting.

 

I would have an individual ground rod at each hut (you can use 2 core to run the sub-mains then).

 

EDIT If you could post a sketch of what the local sparkies are proposing we can give some pointers. It's often better to adapt/correct what someone suggests rather than go in with a new, radical (to them) concept.

 

EDIT2 Are you intending to meter the supply to each hut (to charge or at least monitor your guests)?

 

[harry68]

OK, so you are having a 30/100 meter? (100A maximum)

 

I would run 2-core 25mm2 NYY cable in a conduit underground from meter to the breaker room - Check that your local PEA office are OK with using 2-core, some seem to insist on two single core cables (both can be in the same duct). The breaker room will be your main board as far as PEA are concerned so you'll need a MEN link and ground rod there.

I am going over head wires to the breaker room as existing poles are there

then underground to each hut

 

In the breaker room split the incoming to three sub mains, one for each hut. What load do you anticipate for each hut? How far from the breaker room to the huts?

i would estimate about 10amps be room (12000 BTU a/c and hot water plus the basic lights and power)

 

In each hut have a small distribution board. Size will be determined by what load you are expecting.

 

I would have an individual ground rod at each hut (you can use 2 core to run the sub-mains then).

sorry by 2 core you mean 2 individual wires from each sub main then earth at each hut

 

EDIT If you could post a sketch of what the local sparkies are proposing we can give some pointers. It's often better to adapt/correct what someone suggests rather than go in with a new, radical (to them) concept.

 

EDIT2 Are you intending to meter the supply to each hut (to charge or at least monitor your guests)?

no seperate metres

 

thanks for the help so far much appreciated

[Crossy]

Overhead from the meter to the breaker room makes life easier. Two separate 25mm2 THW on the poles.

 

In each hut:-

• 3.5kW water heater - 15A
• 12000 BTU A/C - 5A
• Ancillaries (lights, TV) - 2 A

Accounting for diversity I'd make each hut a 20A supply.

 

Run 2-core (that's 1 cable with 2 wires) 4mm2 NYY underground in conduit to each hut (use a 32A breaker in the breaker room for each run to the huts).

 

[harry68]

Crossy

you are a champion very much appreciated

ok so i can actually in theory get 30 amps to each hut
as i was told if going to 3 hut using 30 amp i would only get 10 amp to each

 

Cheers

[Crossy]

I'm a little confused as to exactly what type of meter you are getting. The standard sizes are 5/15, 15/45 and 30/100 which provide for maximum loads of 15A, 45A and 100A respectively.

 

Either way there is nothing to stop you pulling the entire available load to one hut, provided the others are drawing nothing. It's the total load that matters and that will be limited by the main incoming breaker in your breaker house.

 

[harry68]

Thanks again Crossy

yes we will be getting 30 amp meter

i already have 2 x 15 amps going to other areas on the property

so now i understand heaps more so a 30 amp meter you can actually load to 100 amps

wow i feel so stupid now

Cheers

[sometimewoodworker]

1 hour ago, harry68 said:

Thanks again Crossy

yes we will be getting 30 amp meter

i already have 2 x 15 amps going to other areas on the property

so now i understand heaps more so a 30 amp meter you can actually load to 100 amps

wow i feel so stupid now

Cheers

that is not stupidity just a lack of knowledge 
 

The numbers on the meters (5/15, 15/30 & 30/100) are the calibration ranges where the meter is guaranteed/most likely to be accurate, you can draw considerably more than the higher number with no problem for the meter (but it may not be reading correctly).

 

So while not recommended 25A, 45A and 140A respectively are not likely to cause any problems as long as the cables are sized correctly. It is likely that if incorrect your bill will record more power used than the real amount.

[harry68]

once again thanks

and with the last bit of info i think that may solve a friends problem with high bills

cheers