Electronics > Power/Renewable Energy/EV's

Wanting to get into solar? Think HOT WATER

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--- Quote from: HackedFridgeMagnet on May 12, 2016, 01:59:37 am ---Some other of advantages of Solar HW over PV hot water.

far less regulatory and safety issues/requirements/costs.
less safety issues/requirements.
--- End quote ---

--- Quote from: HackedFridgeMagnet on May 12, 2016, 03:18:31 am ---I suppose if you keep the PV below 120V in you can do the wiring yourself, but most people in Australia have the grid connect system, so it is highly regulated.
--- End quote ---

--- Quote from: HackedFridgeMagnet on July 07, 2016, 03:44:43 am ---In Australia only electricians should be wiring systems above 120V DC.
--- End quote ---
All wrong. We are talking about modifying or controlling the hot water system, nothing to do with grid inverters, and no fixed mains wiring. This requires no regulatory oversight for a DIY project, no licenses, nothing. Stop perpetuating these messages, or show the regulations/legislation to which they would need to meet.


--- Quote from: HackedFridgeMagnet on July 07, 2016, 03:44:43 am ---
--- Quote from: Zeranin on July 07, 2016, 02:10:11 am ---has no maintenance or reliability issues

--- End quote ---
FYI Hot water tanks are not completely reliable nor maintenance free. Especially if your water is hard. The tempering valves do fail. The elements and thermostats also fail.
Obviously these issues affect both Direct HW and PV hot water though.
I don't see how you can claim your system is lower maintenance when much of the stuff is the same.
I have done very little maintenance on my Solar HW system and it has been running a long time.

Also about your economics, and as it may apply to other people. If you use your house as an example you should include some of  the cost of your solar system which seems to be huge. (?10kw)

Freezing and boiling are not issues for me either. I have a 20 or 30 tube system, i bought it long ago so I cant remember.

These all point to the fact that so much depends on specific circumstances, so you should do a proper analysis before you design or choose your system.
When designing, often the difference between say 85% and 95% solar power is not worth the extra up front cost if you have effective backup.
Also if you DIY then be aware of the regulatory issues and how it could possibly effect your insurance.
In Australia only electricians should be wiring systems above 120V DC.

--- End quote ---

Yes, HW tank issues issues affect Direct and PV hot water equally. However, you are quoting me out of context, for I was comparing my PV resistively-heated water with heat-pump hot water, and I think we would both agree that a stainless steel tank with $30 replaceable element will be a lot more reliable and long-lived than a heat pump. I surfed various forums to gauge people’s experience with heat pump reliability, and concluded that they are often an infinite problem source and money sink.

As to comparing complexity and reliability of Direct and PV hot water systems, they probably come in about the same, if you compare a Direct system with a mains voltage inverter/PV system that is dedicated entirely to producing hot water, but that will almost never be the case. In practice, the homeowner will already have or decide to have a grid-tied PV system, for all of the financial and environmental benefits that it provides in it’s own right. Then, the choice is between building a separate solar HW system, with collectors, pumps, plumbing, controller, backup etc, or adding a simple diverter module to send excess PV power to an electric storage tank. There simply is no argument about which is simpler and will be more reliable, and these days it is likely that the PV HW solution (added to a PV system that you have or plan to have anyway) will be cheaper as well. But if roof area is scarce, that could change everything.

I have been-there-done-that. When I first planned the PV system, I dutifully set aside an additional area of roof for my solar HW system. The fortunately I saw the light and realized that I would be bonkers to build two separate systems, and instead opted for a few more PV panels so that the PV system could do both. I have never looked back. My good mate with his 60 evacuated tubes would not go down that path if he had his time again. That system has cost him a small fortune, and all it can do is produce hot water, and it doesn’t even do that as well as my PV HW system. He is now a complete convert to PV diverted hot water, and is an engineer in an Australian company that is is building and selling PV diverters. I have no connection with the company BTW :) The writing is on the wall. Sales of direct solar HW systems have stagnated, while the popularity of PV HW is increasing. The times, they are a changin …

FYI, my PV system has a 6kW inverter, but about 10kW of panels, to compensate for severe shading in winter. The net result is that the performance in winter is about the same as an unshaded 6kW system. So it’s a respectable sized system, but certainly not huge. You can buy a 6kW system these days surprising cheaply and, as I have demonstrated, you can do a lot of useful things with that power – power your house, reverse-cycle heat and cool your house in the daytime, make hot water, and sell what is left over.


--- Quote from: HackedFridgeMagnet on July 07, 2016, 03:52:52 am ---I was thinking Zeranin that you should use your Hot water for Hydronic heating so you dont use the straight electric Heaters at night.
Just an idea.

--- End quote ---

Actualy a bad idea in my particular case. At night I use natural gas heating. My hot water production in winter using excess PV power just nicely matches my HW usage, with 2 adults in the house, so there is none left over for heating the house at night. It is much more efficient (x3 better) to use my excess PV power during the day to heat the house using reverse cycle, so that's what I do. It's true that I have excess PV power coming out of my ears in summer, even with the hot water production, which I use for cooling the house on very hot days, and the rest gets squirted out onto the grid so others may use it. I get paid handsomely for every kWh that the panels produce, so financially it makes no difference to me whether I use the PV power, or push it onto the grid, so it makes financial sense that I usefully use as much as possible to reduce my power and gas bills. Such ridiculously generous gross feed in tariff schemes are no longer available.

This legislation is done on a state by state basis.

each state has a definition of what is 'electrical work'.

from about page 24.  sorry its so long but I'm sure someone (lower case)  ;) would complain if I cut part of it out.

--- Quote ---18
Meaning of
electrical work
Electrical work
connecting    electricity    s
upply    wiring    to    electrical
equipment  or  disconnecting 
electricity  supply  wiring
from electrical
 equipment; or
manufacturing,    constructing,    installing,    removing,
adding,    testing,    replacing,   
repairing,    altering    or
maintaining    electrical    equi
pment    or    an    electrical
Examples of electrical work—

installing low voltage electrical wiring in a building

installing   electrical   equipment   into   an   installation   coupler   or

replacing a low voltage electrical
 component of a washing machine

maintaining an electri
city entity’s overhead
 distribution system
Electrical work
 does not include the following—
[s 18]
Electrical Safety Act 2002
Part 1 Preliminary
Current as at 8 April 2016
Page 25
Authorised by the Parliamentary Counsel
work that involves connecti
ng electrical equipment to an
electricity  supply  by  means  of
  a  flexible  cord  plug  and
socket outlet;
work   on   a   non-electrical   
component   of   electrical
equipment,  if  the  person  carr
ying  out  the  work  is  not
exposed to an electrical hazard;
Examples for paragraph (b)—

painting electrical equipment covers

repairing hydraulic
components of an electrical motor

replacing a drive be
lt on a washing machine
replacing   electrical   equipment   or   a   component   of
electrical equipment if
 that task can be safely performed
by a person who does not have
expertise in carrying out
electrical work;
Examples for paragraph (c)—

replacing a fuse

replacing a light bulb in a light fitting
assembling,  making,  modify
ing  or  repairing  electrical
equipment  in  a  workplace  under  the 
Work  Health  and
Safety Act 2011
 that is prescribed under a regulation for
this  paragraph,  if  that  is 
the  principal  manufacturing
process at the workplace, and
arrangements are in place,
and are detailed in written form, for ensuring that—
the work is done safely and competently; and
(ii)    the equipment is tested to ensure compliance with
relevant standards;
building   or   repairi
ng   ducts,   conduits   or   troughs
(channels) where electrical wiri
ng will be or is installed,
the channels are not intended to be earthed; and
(ii)    wiring  installed  in  the  channels  is  not  energised;
(iii)  the work is done under
the supervision of a person
licensed to perform electrical installation work;
[s 18]
Electrical Safety Act 2002
Part 1 Preliminary
Page 26
 Current as at 8 April 2016
Authorised by the Parliamentary Counsel
locating  or  mounting  elect
rical  equipment,  or  fixing
electrical   equipment   in   plac
e,   if   this   task   is   not
performed  in  relation  to  th
e  connection  of  electrical
equipment to an electricity supply;
assisting   a   licensed   electrical   worker   to   carry   out
electrical work, on
electrical equipmen
t under the direct
supervision  of  the  electrical
  worker,  if  the  assistance
does  not  involve  physical  co
ntact  with  any  energised
electrical equipment;
carrying   out   electrical   
work,   other   than   work   on
energised   electrical   equi
pment,   in   order   to   meet
eligibility   requirements   in
   relation   to   becoming   a
licensed  electrical  worker
  and  only  if  the  work  is
prescribed under a regulation for this paragraph;
building,  under  the  supervis
ion  of  an  elect
ricity  entity,
an  overhead  electric  line 
on  structures  that  do  not
already carry an energised overhead electric line;
laying,  cutting  or  sealing 
underground  cables  that  are
part of the works of an electri
city entity before the initial
connection of the cables to an electricity source;
recovering underground cables th
at are part of the works
of  an  electricity  entity 
after  disconnection  from  an
electricity source;
altering,    repairing,    main
taining    or    recovering    an
overhead  electric  line  that 
is  part  of  the  works  of  an
electricity  entity,  if  the  work  is  performed  under  the
entity's supervision and—
if  the  line  is  not  on 
supports  supporting  another
electric  line—the  line  h
as  been  isolated  from  an
electricity source so that
the closure of a switch can
not  energise  the  section  of  the  line  where  work  is
being done; or
(ii)    if the line is on supports
 supporting another electric
line—both   lines   have   been   isolated   from   an
electricity source so that
the closure of a switch can
not energise the section of
 the line where the work
[s 19]
Electrical Safety Act 2002
Part 1 Preliminary
Current as at 8 April 2016
Page 27
Authorised by the Parliamentary Counsel
is  being  done  or  an  adj
acent  section  of  the  other
(m)   erecting    structures    for   
the    support    of    electrical
Examples of structures—

electric poles and towers
locating,    mounting    or    fi
xing    in    place    electrical
equipment, other than—
making or terminating elec
trical connections to the
equipment; or
(ii)    installing  supply  conducto
rs  that  will  connect  the
equipment to a supply of electricity;
maintaining the structural pa
rts of the electrical traction
system  on  a  railway,  other  than  overhead  electric  lines,
that forms part of the works of
 an electrical entity, if the
work  is  structural  work 
performed  under  a  safe  system
of work.
Types of electrical work for this Act
Electrical installation work
 is electrical work associated with
an  electrical  installation,  but 
does  not  include  the  following
electrical work—
testing,  repairing  or  mainta
ining  electrical  equipment
included in the electrical installation;
electric   line   work   associ
ated   with   the   electrical
Examples of electrical installation work—

installing or altering wiring or fixed appliances in a building

installing or altering a switchboard
Electric  line  work
  is  electrical  work
  associated  with  an
electric line.
[s 20]
Electrical Safety Act 2002
Part 1 Preliminary
Page 28
 Current as at 8 April 2016
Authorised by the Parliamentary Counsel
Examples of el
ectric line work—

erecting  an  aerial  conductor  that
  is  part  of  the  works  of  an
electricity entity or of
an electrical installation

installing or maintaining street lighting circuits

testing   an   overhead   electrical   
line   to   ensure   it   is   correctly
Electrical  equipment  work
  is  electrical  work  other  than
electrical installation work
or electric line work.
Examples of electrical equipment work—

repairing substation
electrical equipment

repairing an electric range, whether
or not it is part of an electrical

installing, jointing or terminating covered cables
--- End quote ---



--- Quote ---4. Meaning of "electrical work"

    (1) Electrical work is any one or more of the following:

        (a) work on the installation, repair, alteration or removal of an electrical circuit or associated fittings, equipment or accessories;

        (b) work on an electrical installation;

        (c) work on the installation, repair, alteration or removal of electrical infrastructure including lines and wires for the generation, transmission or distribution of electricity and also including supporting and protective structures relating to any such equipment, lines or wires;

        (d) work that has been determined by the Regulator, as defined in the Electricity Supply Industry Act 1995, to be regarded as specialist work.

    (2) Despite subregulation (1), electrical work does not include –

        (a) electrical work performed under an electrical safety management scheme approved under Part 8 of the Electricity Industry Safety and Administration Act 1997; or

        (b) any low voltage electrical work on telecommunications equipment that is carried out by technical workers trained in the telecommunications industry; or

        (c) any extra low voltage electrical work if the electrical work is not in a hazardous area as defined by AS 3000; or

        (d) the insertion of a plug into a socket outlet through which electricity is, or is to be, supplied in order to connect an electrical article or an extension cord to an electricity supply; or

        (e) repair work on an electrical article that is, or is to be, operated at a nominal electrical voltage of 250 volts or less with reference to earth and that electrical article, when manufactured, was to be connected to an electricity supply with a plug and cord; or

        (f) the affixing of a plug or socket to an extension cord through which electricity is, or is to be, supplied at a nominal electrical voltage of 250 volts or less with reference to earth.
--- End quote ---

The exceptions are important but I didn't see any that apply to this case.

Pretty sure you cant in QLD and TAS but not sure about NSW.

AFAIK (and I'm not a lawyer) my statements were correct on the regulations anyway.
ps. I dont agree with this level of restriction either.

Planning on getting solar PV grid connect myself soon, but I will have to move/change the Evac tubes to fit it on.


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