Hi, I'm just looking at earthing now and see it mentioned about earthing the negative of the system. I have six panels that will be connected to a Classic then batteries, just a standard system at 24 volts. Where would I ground this setup? Are there any wiring diagrams about?
Thanks,
On the Classic the PV negative and the battery negative are connected to each other. If you ground one, you ground the other.
The Classic has built in GFP. If you ground either your battery or PV negative, you will defeat the GFP.
--vtMaps
You have three choices:
1. Use the classic's GFI.
2. Bond negative to earth in the dc disconnect
3. Run an unbonded 'floating' setup.
Generally youd only do choice 3 for 12 v PWM systems , in RVs etc. Not recomended for higher PV voltages.
Choice 2 is the industry standard
Choice 1 is the now the law. It has some advantages, but some feel they also introduce additional issues. Search this forum for an entensive discussion on teh topic.
Hi, thanks for your reply. Now that I have an Outback inverter which looks to says to bond the negative from the battery to earth, I'll do that. (Choice 2). I'll look at taking a lead from the negative bar to and earth stake. I'll also have an earth stake our by the PV panels for the frame of the panels and one for the pole of the wind generator. I'll need to read the Outback instructions further to see if I bond the 230v neutral to earth as well.
Cheers,
Generally what you want is a single earth bus, with a single unjoined (or irreversibly joined) conductor connected from that bus to the stake. Avoid daisy chains. Tie all metal equipment casings to the bus.
Generally its best to tie all your earth stakes if you can. Some juridictions permit multiple stakes if the distance apart exceeds a certain amount, but there are some down sides. For the AC see http://midniteforum.com/index.php?topic=1775.msg17446#msg17446
Dont forget the SPDs, especially with the turbine in the picture.
The Outback installation says one earth for the DC negative and one for the AC neutral so I'll have to go with that. I'm not sure from the instructions yet if I earth the battery negative and all the metal casings together on one busbar but expect so. Therefore that would also mean the battery negative etc and the AC neutral connected together and earthed which seems odd.
The FX manual has a block diagram that shows three possible earthing configurations. Choose one. The diagram doesnt really go into the details though. Its assumed theres an electrician involved i guess, as their should be. Going the epanel route helps because theres a one less earth bus. If you use a DC disco and an AC load center you inevitably end up with two earth buses, three if you count the one out at the array. The point is to try to get all earths at the same potential. During surges any kind of resistance in the earth system will cause voltage differentials that can cause damage. I suggest you do lots more reading, and get a sparky to look over your plans and sign it off when you are done.
Asdex,
There is, apparently, a lot of useful information concerning safety and earthing outlined and detailed in NZ standard 5033:2014
Problem is the Standards Committee want you to pay several hundred $ to access this document, making it unlikely to be of use to individuals interested in PV RE systems.
dgd
Theres a good summary of NZ/AU solar related standards here:
http://www.seanz.org.nz/files/file/20/Standards+101+Version+1.1.pdf
The key ones are:
AS/NZS 5033:2014
Installation and safety requirements for photovoltaic (PV) arrays
http://shop.standards.co.nz/catalog/5033%3A2014%28AS|NZS%29/view (http://shop.standards.co.nz/catalog/5033%3A2014%28AS%7CNZS%29/view)
AS/NZS 4509.1:2009
Stand-alone power systems - Safety and installation
http://shop.standards.co.nz/catalog/4509.1%3A2009%28AS|NZS%29/view (http://shop.standards.co.nz/catalog/4509.1%3A2009%28AS%7CNZS%29/view)
AS/NZS 4509.2:2010
Stand-alone power systems - System design
http://shop.standards.co.nz/catalog/4509.2%3A2010%28AS|NZS%29/view (http://shop.standards.co.nz/catalog/4509.2%3A2010%28AS%7CNZS%29/view)
AS 4086.2:1997
Secondary batteries for use with stand-alone power systems
Part 2: Installation and maintenance
http://infostore.saiglobal.com/store/Details.aspx?ProductID=310289
And obviously AS/NZS 3000:2007 "Wiring Rules" overarch. I was told that its a legal requirement in NZ for PV installers (including homeowners) to abide by these standards, and they carry $10,000 fines. However its my understanding that if the array Voc is below 120V you can do the work yourself, however the 230V side has to be supervised by a registered electrician.
Hi, thanks for that info. My PV voltage will be under 120v and despite my obvious ignorance of things solar I am a reg electrician so will be fine with the 230v side. I downloaded a copy of the ASNZS5033-2014 so will have a read.
Cheers,
I had a quick look and the only ones i was able to find free online are:
https://law.resource.org/pub/nz/ibr/as-nzs.4509.2.2010.pdf
http://docs.niwa.co.nz/library/public/AS4086.2-1997.pdf
Quote from: zoneblue on November 25, 2014, 01:42:13 PM
...
I was told that its a legal requirement in NZ for PV installers (including homeowners) to abide by these standards, and they carry $10,000 fines.
Don't think so otherwise there would be several million in fines due for collection.
Sounds like one of the ususal scam tactics to leverage $ out of home owners interested in RE.
Never heard of a PV installation inspector either.
Quote
However its my understanding that if the array Voc is below 120V you can do the work yourself, however the 230V side has to be supervised by a registered electrician.
...thought it was 50v mentioned in one of the standards? I got the impression this was to make allowance for the RV/Motorhome people on 12v systems.
dgd
ELV is 50V RMS AC, 120V DC, ripple free. Thats defined in AS/NZ3000, which is eqiv to US NEC.
Heres an recent example of a fine being levied: http://www.nzherald.co.nz/northern-advocate/news/article.cfm?c_id=1503450&objectid=11107253
At the top of the food chain is the Electricity Act 1992 (http://www.legislation.co.nz/act/public/1992/0122/latest/DLM281858.html):
108. Restrictions on doing or assisting with prescribed electrical workâ€"
(1 ) Subject to section 101 and sections 109 to 113 of this Act, no person shall do any
prescribed electrical work, or assist in doing any prescribed electrical work, unless
that person is authorised to do so under this section.
The penalties for non compliant electrical work in NZ are spelled out in the Electricity (Safety) Regulations 2010 see http://www.legislation.co.nz/regulation/public/2010/0036/latest/whole.html
13. Doing work on works, installations, fittings, and appliances
(1) A person who does work on any works or installation, or on any part of any works or installation, must ensureâ€"
(a) that the resulting works or installation, or part of the works or installation, is electrically safe; and
(b) if the work is on only part of any works or installation, that the work has not adversely affected the electrical safety of the rest of the works or installation.
(2) A person who does work on any fittings or appliances must ensure thatâ€"
(a) the resulting fittings or appliances are electrically safe; and
(b) in the case of mining electrical equipment or conductors supplying that equipment, the resulting equipment and conductors comply with the applicable requirements of Part 5A and Schedule 8.
(3) A person who does work on any works, installations, fittings, or appliances must, while doing the work, take all practicable steps to ensure that people and property are protected from dangers arising from the work.
(4) In this regulation, work includes doing, or supervising the doing of, any of the following:
(a) constructing, manufacturing, or assembling:
(b) installing or connecting:
(c) maintaining:
(d) testing, certifying, or inspecting.
(5) A person commits an offence and is liable on conviction to a level 2 penalty if he or sheâ€"
(a) does work on any works or installation and fails to comply with subclause (1); or
(b) does work on any fittings or appliances and fails to comply with subclause (2); or
(c) while doing work on any works, installations, fittings, or appliances, fails to take all practicable steps to ensure that people and property are protected from dangers arising from the work, where the person doing the work knows, or can reasonably be expected to know, of the dangers that may arise from the work.
And the AS/NZ standards are brought into play in section 60:
60. Certain installations must comply with Part 2 of AS/NZS 3000
(1) The following installations or part installations must be installed, tested, inspected, and connected so as to comply with Part 2 of AS/NZS 3000 and also with the standard indicated:
(a) an installation or part installation intended for use with electrical medical devices: AS/NZS 3003:
(b) an installation or part installation in a hazardous area: AS/NZS 60079.14:
(c) a connectable installation or part of a connectable installation in a mobile medical facility: NZS 6115:
(d) a connectable installation or part of a connectable installation in a pleasure vessel: AS/NZS 3004.2:
(e) all other connectable installations or parts of connectable installations: AS/NZS 3001:
(f) a site installation or part of a site installation thatâ€"
(i) is in a marina: AS/NZS 3004.1; or
(ii) is in a show or carnival: AS/NZS 3002; or
(iii) is intended to supply connectable installations in mobile medical facilities: NZS 6115; or
(iv) is intended to supply any other connectable installation: AS/NZS 3001.
(2) If any of the following are installed so as to comply with Part 2 of AS/NZS 3000, they must also comply with the standards indicated:
(a) a refrigeration system (but not a refrigeration appliance): AS/NZS 1677.2:
(b) an animal stunning or meat conditioning system: NZS 6116:
(c) a stand-alone power system: AS/NZS 4509.1:
(d) a photovoltaic array: AS/NZS 5033:
(e) an emergency power supply in a hospital: AS/NZS 3009:
(f) a low voltage mains parallel generation system that is connected to the national grid: AS/NZS 3010 and AS 4777.1.
The fines are spelled out in sections 10 through 12.
Sadly it appears that we live in a highly regulated society.
However i get the impression that these regs are in the process of moving to more effects based wording. Hence the emghasis of the language above is about practices. "A person who does work on any works or installation, ... , must ensure... that the ... works or installation, is electrically safe", as defined in the standards. However as usual its a quagmire of subclauses, and there are certain things that you are allowed to do and not allowed to do, as homeowners.
For instance section 57 explicitly spells out things you may do:
57. Exemption for domestic electrical wiring work
(1) A person who carries out prescribed electrical work in reliance on the exemption in section 79 of the Act (exemption for domestic electrical wiring work) must carry it out, and test the work, in accordance with ECP 51.
(2) For the purposes of section 79(1)(a) of the Act, the domestic electrical wiring work that an owner of premises may do is work of any type described in subclause (3) on a domestic installation that has a maximum demand at or belowâ€"
(a) 80 amperes per phase if single-phase; or
(b) 50 amperes per phase if multi-phase.
(3) The work to which subclause (2) relates is any of the following:
(a) removing and replacing fuse links:
(b) connecting and disconnecting fixed-wired appliances:
(c) relocating existing switches, socket-outlets, and lighting outlets that are supplied with electricity by tough plastic-sheathed cables:
(d) removing and replacing any of the following kinds of fittings (but only if the work does not involve work on a switchboard):
(i) switches, socket-outlets, and light fittings:
(ii) permanent connection units, ceiling roses, cord-grip lampholders, and flexible cords connected to any of them:
(iii) batten holders:
(iv) water heater switches:
(v) thermostats:
(vi) elements:
(e) installing, extending, and altering subcircuits (including submains), but only ifâ€"
(i) the person does not enter (whether directly, or by holding any material or equipment, or otherwise) any enclosure where live conductors are likely to be present; and
(ii) the work is tested and certified in accordance with Part 2 of AS/NZS 3000, before being connected to a power supply, by a person authorised to inspect mains work.
The regulation also makes references to these ECP regulations:
ECP 35 New Zealand Electrical Code of Practice for Power Systems Earthing (NZECP 35:1993)
ECP 50 New Zealand Electrical Code of Practice for Repair and Maintenance of Domestic Electrical Appliances by the Owner of the Appliance (NZECP 50:2004)
ECP 51 New Zealand Electrical Code of Practice for Homeowner/Occupier's Electrical Wiring Work in Domestic Installations (NZECP 51:2004)
These are available to download at http://www.med.govt.nz/energysafety/legislation-policy/electricity-acts-regulations-codes/standards-and-codes-of-practice/new-zealand-electrical-codes-of-practice
However PV installations are classified as high risk and thus subject to compliance certification, and thus registered electricians. See sections 6A and 65.
If you want a shorter answer then youll need a lawyer. ;)
ZB
Just a cursory glance at some of these documents convinces me they were written by lawyers for lawyers. It also appears that legal enforcement of these depends on a complaint from someone dissatisfied with an installer/electrician/etc. And so it should be.
With 5033:2014 not being freely available its usefulness to the RE enthusiast (with off-grid or even grid tied RE systems) is very doubtful.
I can just imagine that the preliminary thought on any RE enthusiasts mind before they start considering the design or implementation of their RE system, is to spend over $250 purchasing 5033:2014 from the Standards Committee.
Its a copyrighted document too so no distributing unauthorised (ie paid for) copies unless you have Dotcom rights. :P
dgd
I don't know about down under but in Canada it would be legal if for educational purposes... From Wiki:
Fair dealing is a statutory exception to copyright infringement. It is a defence, with the burden of proof upon the defendant. To qualify under the fair dealing exception, the dealing must be for a purpose enumerated in sections 29, 29.1 or 29.2 of the Copyright Act of Canada (research, private study, education, parody, satire, criticism or review and news reporting), and the dealing must be fair.
i have found the E-panel diagram from Midnite which I think will have some useful info on earthing and setting up my system.
Cheers,
that epanel simplifies it, to my mind, as the disco is considered the main switchboard, with its main earth bus and grounding conductor. Any additional load center becomes a DB, which is allowed a chained earth bus, per chapter 5.
The probem is Im just not that keen on putting ac and dc in the same enclosure, because of the 50mm proximity rule.
However my reading of Wiring rules suggests no one particular right way to operate both dc and ac ground buses. The obvious choices are:
A- two stakes
B- two main grounding conductors
C- run dc earth off the ac earth bus
D- vice versa.
if the ac center is considered both main swb and db, ie single men neutral bond is there, and given the higher voltages there ive generally always gone with B. The code uses the word "directly" now, whereas it used to say, in my day, unjoined or irreversibly joined.
And BTW all 900 pages of NEC 2014 are now available Creative Commons, see
https://archive.org/details/nfpa.nec.2014
Articles 690 and 250 go into PV and Grounding extensively.