BS機電工程討論區，歡迎所有機電問題

rcbo 可以比ev charger

另外行ring同radial係睇用途，好處同壞處，唔話管死

新例係咁要求，但到依家都係用2500V

你啱
上面講嘅RCCB係要配埋MCB, 同埋只要你搵到啱用嘅RCBO貨期又啱水，全部都可以用一隻RCBO搞掂哂

可唔可以講下VRV 基本操作

留名學野

好耐無理過thd了

貨期又啱心*水
因為啲特別款式嘅RCBO比較難買, RCCB + MCB易啲搵到

點分等電位區域內/外?

留名學野

長知識

不過5秒會否太少
個test應該都係1分鐘

呢個5秒出處係邊？61439-1 冇mention

2021 version clause 10.9

https://library.e.abb.com/public/57756bd5fffd72fac12579ca002d8907/k0119_the_new_iec_web.pdf

Page 7 also mentioned by ABB

https://library.e.abb.com/public/32f98df19e5849e1b6b5d6172e00be73/2CPC000313B0201.pdf

Page 147

依家無份code係手

其實ring circuit係uk前朝遺物

如果你個source同loads隔得遠
咁你啲loads拖完手仔，
拖多條線返返去電箱，咁就唔洗用咁粗
但相對地你要拉多條線
(同一個volume嘅copper 一拆二, 兩條個surface area加埋唔係double)

ring你有兩條線，volt drop細咗， 可以俾得多啲load

唔好處係斷一邊仲會正常但隨時overload著火，家用線係好cheap冇防火冇低煙無毒

但香港啲人見到COP寫100sqm就梗係狗衝ring circuit啦

短路斷電都係得一隻MCB同水氣掣
香港因為係穿暗喉，人工貴過料
所以做ring反而變咗高級啲

不過香港啲電線衰極都有張cert, 好少出事。 ring同radial分別不大。

不過UK開始知驚就叫你啲人考慮裝AFDD

有冇師兄開始要裝AFDD

屌痴線

個5s係10.9.2.3 Application of the test voltage


個test係10.9.3 Impulse withstand voltage入面嘅10.9.3.3


你份野錯啦


10.9.2.3 講緊點樣apply個voltage
一開始唔好過50% full test value
然後要扭上去100% full test value
keep住5s

唔係話試5s就得

試幾耐係根據10.9.3.1
睇下試lightning impulse 定試power frequency


佢冇寫試幾耐
但ABB寫最少一分鐘
我理解係1分鐘

你想講用remote / controller 定真係OU IU 開機
其實佢送貨果時都有說明書有講點用

睇樓主答既野又唔係幾似地盤佬

巴打有幾條問題想問你
1. Cable 點Sizing？
2. 消防/花曬水缸點Sizing？
3. 點選擇消防泵？
4. Pre-cal有咩要求要fulfill?
5. Booster Pump咩情況要用？
6. 天台泵房仲有咩要裝？

1. 點樣Cable Sizing, 之前已經講過點樣Sizing Protective Device, 入面提到要 Ib<=In<=Iz, 我要黎緊就係要搵Iz出黎, Iz 係指current carrying capacity, 搵到Iz就可以用COP個表搵番邊一個Rating既Cable岩用, Iz係用你In個數x Correction Factor, Correction Factor係COP Table A5度有寫, 我地主要睇兩個Ca (Ambient Temperature Factor)同Cg (Grouping Factor), Ci (Protective Device Factor)同Ci (Insulation Factor)就比較少會需要考量到, 所以呢d剩係提Ca同Cg呢兩個factor, Ca睇COP Table A5(1)可以搵到, 但要搵Ca你首先要知自己用咩type既Cable先, 係1/C定4/C, 有Amour定冇Amour, 知道左之後去Table A6, 搵番你個種Type既Cable, 個表會有寫住個隻Cable既Operating Temperature, 你就係要拎呢個Operature Temperature去番Table A5(1), Type of insulation 個度搵番你個Operature Temperature, 之後你要預你Cable工作環境既ambient temperature, 呢個數就你自己Design, 當你預35度, 咁你Ca就係0.96, 搵完Ca就到搵Gg, 即係Cable既Grouping Factor, 呢part要你知道你條Cable打算用咩Cable containment, 係行Cable Tray, Trunking 定就咁surface mounted, 呢part除左要睇Table A5(2)之外, 仲要睇Reference Method, COP Appendix 7列左一大堆Installation Method, 佢編左個英文號碼比每個Installation Method, 你搵番你個英文號碼, 再去番Table A5(2), 之後你就用你手頭既資料搵番個Factor, 當你搵到係0.79, 咁你Cg就係0.79, 搵哂Ca同Cg之後, 就可以去搵個Correction Factor, Correction Factor = 1/(Ca x Cg) = 1.3186, 有左Correction Factor 就拎呢個數x你Protective Device個Rating, 呢度唔係拎Design Current黎x, 係因為要確保 Ib<=In<=Iz, 當你Protective Device 個Rating係400A, 咁你Iz就= 400 x 1.3186 = 527.44A, 有左呢個數就去番你係搵Ca個陣, 去過Table A6個頁, 呢度都會用到你個Reference Method, 搵番你要既Cable Type, Reference Method, 之後就搵下個一列, 你要搵一條Cable個A數大過你計數得出黎既Iz, 當你Single-core armoured XLPE insulated cables, Reference Method C, 3 or 4 cable, three-phase, 咁你最少要選擇240mm sq既cable先得, 咁樣你就初步地design左cable size, 但你仲要check多兩樣野, 一個叫Voltage Drop, 另一個叫Copper loss, Voltage Drop係指你條Cable本身有電阻值, 係電流經過Cable去你最終目的時, 會有電壓降影響個系統, 跟COP例電壓降唔可以大過4%, 要計番個Voltage Drop就需要知你Cable既長度, 當你長度50m, 你仲要搵埋你電線既Cable Impedance, 呢個數會係Table A6搵番你用個條Cable, 岩岩我地簡左240mm sqmm (Single-core armoured XLPE insulated cables), Table A6(7)除左CCC之外, 仲有一頁叫Voltage Drop, 你可以係個頁搵番個z值, 呢度我當0.37mV/A/m, 之後就夠料計個Voltage Drop, Voltage Drop = (Ib x z x Length / 1000 x 380) x 100%, 之後就睇會唔會大過4%, 計完Voltage Drop之後, 就要計Copper Loss, Copper Loss唔係睇COP, 而係睇BEC (Building Energy Code) Electrical, 係7.4.2入面會講左一大段野, 意思係指
Main Circuit (CLP去總掣房) < 0.5% Copper Loss
Feeder Cable (由總掣房去你供電個一層既電錶房) < 1.5% Copper Loss
Submain Cable (L<100m) (由你電錶房去你供電個間房) < 1.5% Copper Loss
Submain Cable (L>100m) (由你電錶房去你供電個間房) < 2.5% Copper Loss
Final Circuit (由你供電個間房去到你最終電路) < 1% Copper Loss
你要逐Part逐Part計番每一Part會唔會超過BEC個要求, 當你計哂Copper Loss 同 Voltage Drop, 如果發現fulfill 唔到就要番番去簡Cable個Part, 再簡個一條Cable, 直到能夠Fulfill到為止

1. 點樣Cable Sizing, 之前已經講過點樣Sizing Protective Device, 入面提到要 Ib<=In<=Iz, 我要黎緊就係要搵Iz出黎, Iz 係指current carrying capacity, 搵到Iz就可以用COP個表搵番邊一個Rating既Cable岩用, Iz係用你In個數x Correction Factor, Correction Factor係COP Table A5度有寫, 我地主要睇兩個Ca (Ambient Temperature Factor)同Cg (Grouping Factor), Ci (Protective Device Factor)同Ci (Insulation Factor)就比較少會需要考量到, 所以呢d剩係提Ca同Cg呢兩個factor, Ca睇COP Table A5(1)可以搵到, 但要搵Ca你首先要知自己用咩type既Cable先, 係1/C定4/C, 有Amour定冇Amour, 知道左之後去Table A6, 搵番你個種Type既Cable, 個表會有寫住個隻Cable既Operating Temperature, 你就係要拎呢個Operature Temperature去番Table A5(1), Type of insulation 個度搵番你個Operature Temperature, 之後你要預你Cable工作環境既ambient temperature, 呢個數就你自己Design, 當你預35度, 咁你Ca就係0.96, 搵完Ca就到搵Gg, 即係Cable既Grouping Factor, 呢part要你知道你條Cable打算用咩Cable containment, 係行Cable Tray, Trunking 定就咁surface mounted, 呢part除左要睇Table A5(2)之外, 仲要睇Reference Method, COP Appendix 7列左一大堆Installation Method, 佢編左個英文號碼比每個Installation Method, 你搵番你個英文號碼, 再去番Table A5(2), 之後你就用你手頭既資料搵番個Factor, 當你搵到係0.79, 咁你Cg就係0.79, 搵哂Ca同Cg之後, 就可以去搵個Correction Factor, Correction Factor = 1/(Ca x Cg) = 1.3186, 有左Correction Factor 就拎呢個數x你Protective Device個Rating, 呢度唔係拎Design Current黎x, 係因為要確保 Ib<=In<=Iz, 當你Protective Device 個Rating係400A, 咁你Iz就= 400 x 1.3186 = 527.44A, 有左呢個數就去番你係搵Ca個陣, 去過Table A6個頁, 呢度都會用到你個Reference Method, 搵番你要既Cable Type, Reference Method, 之後就搵下個一列, 你要搵一條Cable個A數大過你計數得出黎既Iz, 當你Single-core armoured XLPE insulated cables, Reference Method C, 3 or 4 cable, three-phase, 咁你最少要選擇240mm sq既cable先得, 咁樣你就初步地design左cable size, 但你仲要check多兩樣野, 一個叫Voltage Drop, 另一個叫Copper loss, Voltage Drop係指你條Cable本身有電阻值, 係電流經過Cable去你最終目的時, 會有電壓降影響個系統, 跟COP例電壓降唔可以大過4%, 要計番個Voltage Drop就需要知你Cable既長度, 當你長度50m, 你仲要搵埋你電線既Cable Impedance, 呢個數會係Table A6搵番你用個條Cable, 岩岩我地簡左240mm sqmm (Single-core armoured XLPE insulated cables), Table A6(7)除左CCC之外, 仲有一頁叫Voltage Drop, 你可以係個頁搵番個z值, 呢度我當0.37mV/A/m, 之後就夠料計個Voltage Drop, Voltage Drop = (Ib x z x Length / 1000 x 380) x 100%, 之後就睇會唔會大過4%, 計完Voltage Drop之後, 就要計Copper Loss, Copper Loss唔係睇COP, 而係睇BEC (Building Energy Code) Electrical, 係7.4.2入面會講左一大段野, 意思係指
Main Circuit (CLP去總掣房) < 0.5% Copper Loss
Feeder Cable (由總掣房去你供電個一層既電錶房) < 1.5% Copper Loss
Submain Cable (L<100m) (由你電錶房去你供電個間房) < 1.5% Copper Loss
Submain Cable (L>100m) (由你電錶房去你供電個間房) < 2.5% Copper Loss
Final Circuit (由你供電個間房去到你最終電路) < 1% Copper Loss
你要逐Part逐Part計番每一Part會唔會超過BEC個要求, 當你計哂Copper Loss 同 Voltage Drop, 如果發現fulfill 唔到就要番番去簡Cable個Part, 再簡個一條Cable, 直到能夠Fulfill到為止

2. 消防/花灑水缸點樣Sizing?
消防水缸Sizing主要跟消防處COP 5.26 Supply Tank, 你要知你Building既GFA面積, 個頁有個表比你, 9000L, 18000L, 27000L, 36000L, 你知GFA面積就可以搵到個FS Service Tank size, 而花灑水缸要首先知你用咩方法去做Design, Sprinkler design有兩種, 一種係Pre-calculation, 一種係Fully Hydraulic Calculation, 主要Pre-calculation係跟住BSEN12845入面d表去做sizing, Fully Hydraulic 個水缸就係計數計出黎, 通常我地都係用Pre-calculation去做, 除非Fulfill 唔到Pre-calculation既要求 (Sprinkler Control Valve到Design Point < 0.5bar 同Supply Tank 到 Sprinkler Control Valve跟唔到BSEN12845表要求), BSEN12845 Part 9.3.2.2入面有個表寫LH同OH Hazard level既sprinkler水缸最少要幾大, Hazard level, Dry , Wet, pre-action, alternate係咩, 呢part就唔講啦, 香港9成係用OH Hazard level + Wet type system, 你自己上網查下, 咁就大致上講左點樣Sizing 水缸

volt drop 太大 想轉用 5.5kV
有咩例/guide 跟？