Controller amps and elements

[Mr B]

S.E - Thank you for reminding me of earlier posting relating to my question.

However, this is a thread to inform on the subject, and not to slander other forum members.

My questions relate to the capacity of legally installed circuitry, and what I should be utilising this for.

Please, if you have anything useful to contribute, then contribute, otherwise, do not.

Thanks.

 

[Camo6]

Thanks Sponge

Interesting. Does this mean that they will supply 20a?

I thought that general house circuitry, apart from dedicated 15A or higher circuits were 10A, largely due to the standard wire size used to feed them?

Being that I would like to use RCD protected circuits, does this mean that I can/could/should not e.g. run a 3600w element off P1 and P2?

Or use the 15A curcuit?

The breakers were obviously installed by a sparky, is the install okey dokey? Will those breakers protect from fire etc?

They will trip at 20A which is why they're labelled a 15A supply as you want to run lower currents than the trip current. Maximum current carrying capacity of cables varies greatly depending on their location and arrangement. A cable hanging in the air can disperse a lot more heat than one surrounded by insulation. But that's why circuit protective devices are installed to trip well below that capacity.
The P1 and P2 C20's in your pic are combined circuit breakers and RCD's. the test button is to test the RCD function. The circuit breaker function will trip at 20A and unless your circuits are wired in 1.5mm2 you'd probably be safe. But as none of us can certify that I'd be getting a sparky to confirm.


Edit: Flick your CB's individually and use a lamp or multimeter to confirm which GPO's are on which circuit. If they're only on a CB (no test button) get a sparky to replace all the MCB's with RCBO's which will protect both circuit and you.

 

[S.E]

S.E - Thank you for reminding me of earlier posting relating to my question.

However, this is a thread to inform on the subject, and not to slander other forum members.

My questions relate to the capacity of legally installed circuitry, and what I should be utilising this for.

Please, if you have anything useful to contribute, then contribute, otherwise, do not.

Thanks.

No slander intended and I’m surprised you saw it that way. just a light hearted tong in cheek pull up of Stu’s questionable double standards. After all where do you draw the line on advising.

 

[Mr B]

No slander intended and I’m surprised you saw it that way. just a light hearted tong in cheek pull up of Stu’s questionable double standards. After all where do you draw the line on advising.

Ok mate, glad we will stay on topic then. Bit of 'stuff' in other threads, not necessary here.

Cheers

 

[Ducatiboy stu]

.

 

[TheWiggman]

I'm not a sparky but I would be following Camo's advice on this one.

 

[Ducatiboy stu]

Camo

"Maximum current carrying capacity of cables varies greatly depending on their location and arrangement. A cable hanging in the air can disperse a lot more heat than one surrounded by insulation "

Very true

.. you also need to take into account where the cable is installed. Cables in a shed ( in summer ) that are installed up against the tin cant carry the same current as cables underground and up thru the floor.

 

[Mr B]

Mmmmm thanks gents.

Noted sparky advice is recommended. Will do this, but would like to get my head around whats going on.

Is it common for a GPO circuit to be 15 amp? Does this indicate that maybe the wrong breakers have been put on? Does the sparky select the appropriate breakers depending on the cabling diameter and install route? Or is it normal for 20a breakers to be put on 10a circuits? Seems like a lot of headroom?

When they do the panel, they certify that it is good and to spec. Does safe utilization rely on people only using common goods which are 10a?

Do all goods which draw more than 10a have a large earth pin (or a 3 phase plug if they are this?) - so that the gpo outlet effectively controls the draw?

Arr, nothings simple. Just looking to understand, not to do any work myself. I value my skin too much

 

[Camo6]

Stu, my cables come straight up from under a slab through two feet of conduit to a double gpo. I did my math. I had seasoned sparkies confirm it. They were originally 15 amp circuits supplying a caravan, I merely restored them to their original purpose after a switchboard upgrade some years prior.

Sorry Mr B for polluting your thread (I'm good at that), but I love these electrical discussions as the theory is still fresh in my head and makes me think. Too be honest, I think far less people are harmed from these threads than some of the others floating around.

 

[Logan_01]

At the end of the day the install looks legit (although now days any power cct or lighting cct must be on rcd). That rule hasn't always applied and does not need to be enforced retrospectively. So in my opinion the cable is protected regardless of the load (max demand by limitation).
So you have two problems.
1. The 10a power points are only designed to carry and switch 10a. So by putting 2400w element + 2 x 1a pumps you will exceed the manufacturers specs. Easy to swap a 10a power point for a 15a, but illegal for a sparky to do as it is against as3000.
2. The 15a cct not being on rcd. Considering the fact that it will supply an element, submersed in water, that you will be in direct contact with, I would definitely have an rcd installed for your safety. That doesnt mean you need a sparky to replace the circuit breaker. You could use a rcd box (external rcd placed inline), as long as it is all rated at > 15a.

All just imho of course.

 

[Camo6]

Mr B, the earth pin merely prevents you plugging a higher drawing load into a 10A GPO. An old trick was to file the earth pin of a 15A plug to fit a 10A GPO. Problem being that A) you potentially reduced the contact are of the earth conductor and B ) you would load the circuit with a higher than expected current. The former is potentially fatal, the latter is poor practice. Most caravan owners will have a 15 to 10A adapter for just that purpose.
The circuit protection device is there to limit the load. It's value is determined by the conditions of the circuit it's protecting. In the old days it was all too easy to replace fuse wire with a heavier gauge. With new regulations it's less likely that a circuit isn't properly protected but from what I've seen in my limited time in the industry it still happens.

Edit: damn emoticons

 

[Pokey]

Mmmmm thanks gents.

Noted sparky advice is recommended. Will do this, but would like to get my head around whats going on.

Is it common for a GPO circuit to be 15 amp? Does this indicate that maybe the wrong breakers have been put on? Does the sparky select the appropriate breakers depending on the cabling diameter and install route? Or is it normal for 20a breakers to be put on 10a circuits? Seems like a lot of headroom?

When they do the panel, they certify that it is good and to spec. Does safe utilization rely on people only using common goods which are 10a?

Do all goods which draw more than 10a have a large earth pin (or a 3 phase plug if they are this?) - so that the gpo outlet effectively controls the draw?

Arr, nothings simple. Just looking to understand, not to do any work myself. I value my skin too much

It's common for multiple 10 amp outlets to be supplied from 1 breaker, the wiring supplying the outlets will commonly be rated to 20 amps. The circuit protection is rated for the fixed wiring not the plugged in wiring or device.
Current drawn by the device is not limited until the circuit protection is tripped. I've seen lots of 15 amp earth pins cut down to fit 10 amp outlets.

 

[rockeye84]

If you have 3 phase available at your place you could have a phase dedicated to your brewery, as I did.

Phase1: electric hot water sys + A/C, kitchen/house circuit

phase 2: electric hot plates + stove, bedroom/laundry

Phase 3: brewery + shed circuit

Had the brewery + dryer + oven + heater going today, yet to pop a main fuse on one of the phases, the wheel on my meter likely came close to breaking the sound barrier tho.

Picked the plug & socket up for $100 second hand, sparkys charged me $300 to install it and re-jig my circuits.

Well worth the investment & beats worrying about what other appliances on or off when your trying to brew..

 

[Ducatiboy stu]

Stu, my cables come straight up from under a slab through two feet of conduit to a double gpo. I did my math. I had seasoned sparkies confirm it. They were originally 15 amp circuits supplying a caravan, I merely restored them to their original purpose after a switchboard upgrade some years prior.

It surprising what you can do if you decide to change the nature of a pair if wires

 

[Mr B]

Thanks gents.

Think that I will:

Determine circuit layout
Consider fitting RCD breakers in the control box so that I could safely use it anywhere
Continue to source suitable parts

Cheers

 

[Ducatiboy stu]

RCD breakers in the box is not a bad idea. Breakers are only about $10-15

They will act as the primary switch and they are quick and easy flick off in case shit goes down.