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Solar Water Heater Safety Setup, Body Metal at the roof top
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TSdavidlow7
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 Jun 15 2022, 12:40 PM, updated 4y ago
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Hi Experts, The new ST guideline 2022 is already out but does not seem to mention the solar water heater at all, despite solar water heater is already so common. https://www.st.gov.my/en/contents/files/dow...N_DOMESTIK1.pdfMy questions are 1. with such a big body metal parts in the solar tank on the roof - does the body need to be earthed? 2. Current earthing is only through the heating element itself (connected via a switch) which has a Ground wire - is this sufficient? Does this also need to have a dedicated RCD 10ma? 3. Water Pump at the roof - since this connects to water source for all bathrooms - does it need to connect to a dedicated 10ma RCD as well? or it is okay connecting to the existing 30ma meant for all 13A socket? Thanks This post has been edited by davidlow7: Jun 15 2022, 04:45 PM |
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TSdavidlow7
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Jun 15 2022, 01:43 PM
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QUOTE(Zot @ Jun 15 2022, 01:18 PM) 1) Solar heater has no electricity to it. Why need electrical Earth? 2) Basically it is sufficient but Earth detection that trigger ELCB will only be triggered when electricity leak is detected in Earth circuit. If current leak through water to your body and to house floor, then it will not trigger the ELCB. This is where RCD is taking charge. However, logically, the heater element leak to water will eventually leak to copper heater housing thus will trigger ELCB. Anyway, having both will ensure fail safe operation. 3) Basically answer is like #2. Yes, no problem being served my existing 30mA I believe. Thanks Zot For #1, there is a heating element in it connected to a 1gang switch which it basically functions to "boil' the water when there isn't sufficient energy generated from the sun but the switch is earthed anyway - just not sure if we need to have a dedicated 10ma for this? 2ndly, do you think the body metal exposed at the top will attract lightning thus need to be earthed (on top of the existing switch)? |
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TSdavidlow7
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Jun 15 2022, 03:27 PM
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QUOTE(Zot @ Jun 15 2022, 01:54 PM) So basically like all other answer. Once there is current leak into water, the current will be conducted through copper and Earth wiring. Yes, lightning is another story. No matter what, I think you would want lightning to strike a lightning arrestor than your heater because that Earth wire is not meant for lightning. The wire will melt on spot if direct hit.  Lightning is attracted to static charge, not the electricity. So, it is the whole house charge , not just the heater there. This is what I know. This is true - Thanks! In this case I will still have its own dedicated 10mA RCD to the switch which links to the backup heater connected in the solar water heater. |
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