電熱水爐點揀？

因為煤氣費貴越來越多人選用電熱水爐，當中三種電熱水爐，儲水式、速熱式及即熱電熱水爐都各有優點。你又知點揀嘛？

電熱水爐主要分三種，分別是即熱式丶速熱式，以及儲水式。

即熱式：即開即有熱水提供。因為利用恆溫器來控制出水溫度，所以不用預熱亦無內置儲水箱，體積較細小。不過在購入安裝前，要留意家局電力輸出功率是否夠大，以及有無足夠水壓及水量。

速熱式：又稱「速龍」，是第三代電熱水爐，加熱速度比傳統儲水式快，只需要大約5分鐘水溫就可升至40°C ，容量可由6L至20L不等。其耗電量比即熱式的低，適合大部份樓宇安裝。

儲水式：設有儲水箱，需要開啟約15-25分鐘才有熱水供應。當開啟熱水爐後，可以直接輸出熱水，而冷水會同時自動注入儲水箱作補充。市面上的儲水式電熱水爐還有分為「無排氣管式」及「花灑式」，前者可提供更大儲水量，能接駁多個出水位，不過需要加設通風設備；而後者儲水量較少，只可接駁一個出水管，不過體積較小，電功率都較低。

耗電量方面，電熱水爐耗電量高，一般家用儲水式、速熱式熱水爐，電功率由 3,000 瓦特 (Watt) 起；即熱式電熱水爐要求較大，電功率會達 7,000W 或以上。

機電工程署早於 2000 年 12 月已推出了儲水式電熱水爐自願性能源效益標籤計劃﹐及後於 2008 年、 2011 年分別作出兩次修訂，想了解各品牌儲水式電熱水爐的能源效益，可以參閱機電工程署網頁。

另外，選購儲水式電熱水爐時，應該按家庭成員數目與用量，選擇合適大小的熱水爐。一般而言，15公升水量足夠一家四口連續使用。

根據水務條例，安裝電熱水爐必須由持牌水喉匠負責或督導，安裝前記得確保安裝人員符合資格。另一方面，在連接電源時，電熱水爐的電線必須直接由總掣拉電線接駁。

如發現電熱水爐水溫忽冷忽熱、有蒸氣、熱水不正常漏出等問題，就應該馬上停止使用，並要盡快找合資格人士作維修。

Color Code of Cable Application in Hong Kong Since 2007

Introduction
With effect from 1 July 2007, colour for identification of conductors in fixed electrical installations has been changed, and the details are shown in Table 1 below and Amendment No. 1:2007 to the Code of Practice for the Electricity (Wiring) Regulations (CoP).

Function	Colour		Letter Code
	Old Colour Code	New Colour Code
Phase of single phase circuit	red (or yellow or white or blue )	brown	L
Phase 1 of 3-phase circuit	red	brown	L1
Phase 2 of 3-phase circuit	yellow or white	black	L2
Phase 3 of 3-phase circuit	blue	grey	L3
Neutral	black	blue	N
Protective conductor	green and yellow	green and yellow	--

Table 1 – Change of Cable Colour Code

The change is applicable to all new electrical installations as well as addition & alteration to existing electrical installations. Existing installations with cables adopting the old cable colour code will not be affected.
A Working Group on the Review of Cable Colour Code in Hong Kong comprising members from the trade and industry was established in year 2003 to study the cable colour change issue in Hong Kong. In mid-2004, the Working Group proposed to adopt the new cable colour code in Hong Kong. The change was then endorsed by the Electrical Safety Advisory Committee in September 2004.
The new cable colour code complies with the requirements of relevant national and international standards (such as IEC 60446, EN 60446, BS EN 60446 and BS 7671) and has been adopted by the majority of the western countries countries (e.g. UK, France, Germany, Spain, Netherlands, Portugal, etc.).

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