Fountains and decorative landscape purposes, usually set in the public areas of openness. In order to increase the decorative effect, water tanks are usually installed in contact with water lantern, sprinkler and some of the supporting electrical wiring. Compared with swimming pools, fountains is an accessible waters in the summer, children playing in the fountains slapstick scene is very common, but there may be more complicated because the pool of electrical installations, compared with pools, fountains security problem is particularly important. Swimming pool, fountains and a wading pool , who want to enter the artificial waters, may install a sprinkler control and decorative electric lighting fixtures, but there is still a need for these electrical wiring system. When a person enters these waters skin may be exposed when the water insulated electrical device or accessory malfunction leakage, water, wet body, electric shock accident prone earth loop composed of the body by the disaster shock. Mandatory standards for construction of electrical area classification by the environment and the surrounding waters, the waters of the swimming pool and other electrical devices, including lighting fixtures, including the proposed safety requirements for swimming pools and similar fixtures of mandatory safety standards LED commercial lighting wholesale also made corresponding requirements.
I. Overview
1. Applicable Standards
Since the normal use of lower body resistance and human contact with the ground, swimming pools, fountains and a swimming pool, an increased risk of electric shock. For electric shock protection devices these regions, we have asked the national swimming pools and similar electrical devices and other pool building, for which the use of lighting, but also the corresponding product safety requirements.
Second, the origin of human exposure threshold voltage safety
Definition of total body impedance and the impedance of the human body and skin impedance vector (see Figure 4). Definition of a human body impedance is the impedance of the second electrode and the body contact between two positions, excluding the skin impedance. Custom skin impedance is the impedance conductive electrode and the subcutaneous tissue between the skin.
Total body impedance varies with the contact voltage of a variable. Total body impedance value is small, in the same circumstances the calculated current through the body, the greater the evaluation results accordingly given more security. Of course, the human resistance is not made as small as possible, so that protective measures would make excessive demands, so that the evaluation results are meaningless. Select the total impedance of scientific and rational human should consider two aspects of various factors directly affect total body impedance, and second, the results of the statistical distribution of the total impedance of the human individual differences in formation. 50Hz/60Hz total body impedance values at higher frequencies due to the capacitance of the skin decreases. Dry conditions, a large contact surface, 50Hz/60Hz AC current path is hand-to-foot, 95% of the measured object incremental value of total body impedance 1000Ω.
a) In dry conditions, a large contact surface, 50Hz/60Hz AC current path of the hands and feet, the safety threshold voltage under 95 percent of human exposure conditions of the test object: Security under dry conditions of human exposure threshold voltage value = body under the current safety threshold × dry conditions the total body impedance = 50mA × 1000Ω = 50V.
b) in wet environmental conditions, a large contact surface, 50Hz/60Hz AC current path of the hands and feet, the safety threshold voltage under 95 percent of human exposure conditions tested object: the person in a humid environment, the human resistance will reduce , dry conditions in the human body is assumed that the total impedance of 100% water
Under wet conditions the total impedance of the human body under dry conditions 50% of the total impedance; human exposure safety threshold voltage under wet conditions = under current safety threshold of human × humid environment of total body impedance = 50mA × 500Ω = 25V ≈ 24V .
c) in saline moist environmental conditions, a large contact surface, 50Hz/60Hz AC current path of the hands and feet, the security threshold voltage at 95% of human exposure condition of the object to be measured: dry conditions assumed impedance of total body 100%, the total impedance of the human body under humid conditions with brine, water wet
Under conditions of 50% of the total impedance of the human body, that is, 25% of the total impedance of the human body under dry conditions. Then, in the saline wet conditions, compared with total body impedance 250Ω, human exposure safety threshold voltage under saline moist environment = lower body current safety threshold × saline moist environment of total body impedance = 50mA × 250Ω = 12.5V ≈ 12V. As the moist environment more suitable for saltwater pool and fountains, therefore, pool and fountain lighting voltage is limited to the use of 12 V ac.
Third, the standard requirements for lamps
1. GB of universal protection requirements 16895.19-2002
Can be seen from Table 2, GB 16895.19-2002 for lighting protection requirements are as follows:
Zone 0: protection requirements lamps using a power supply voltage and operating voltage not exceeding 12Va.c. or 30Vd.c., shell protection grade IPX8.
Zone 1: protection requirements lamps using a power supply voltage and operating voltage not exceeding 12Va.c. or 30Vd.c., shell protection grade IPX5, usually do not wash with water pools IP54.
Zone 2: protection requirements lamps using a power supply voltage and operating voltage not exceeding 50Va.c. or 120Vd.c, and with ≤ 30mA RCD automatically cut off the power supply measures, shell protection grade indoor places IPX2, outdoor places IPX4 partial. sprinkler please wash IPX5.
Special protection requirements 2. GB 16895.19-2002 of
For the lighting of the pool, GB 16895.19-2002 special requirements include:
(1) When using people to enter the zone 0 and 1 in the region can only be fixed luminaires;
(2) located on the rear observation window and from the subsequent irradiation watertight underwater lighting, install it to do does not occur between any conductive part of any exposed conductive parts of lighting fixtures and accessories, and intentional or unintentional observation window conductive connectivity.
(3) shall comply with the requirements of IEC 60598-2-18.
3. GB of safety requirements 7000.218-2008
GB 7000.218-2008 provides swimming pools and similar fixtures with safety requirements, standards regarding lighting classification requirements are very important.
(1) Type of protection against electric shock
Lighting should be protected against electric shock Class Ⅲ lamps, its external and internal operating voltage line should not exceed 12V (12V ac new standard or refined as 30 V dc).
(2) lamps dust and water categories
- Lighting and pool, that part of the water tank is pressurized classification should contact watertight (IPX8);
- Lighting and pool, water tank is not in contact with that part of the classification should be at least as dust and splash-proof (IP54).
(3) The luminaire installation, replacement and power connections in the form of light
-A Category: Power connections and replacement of light fixtures on the side not in contact with water;
Class-B: part or all of the drained pool water, the water from the side in contact with the lamp replacement light source;
-C class: Remove from the water after replacing the lamp light.
Fourth, the other electrical devices required
Of course, swimming pool, LED commercial lighting wholesale is a system problem, not only with lamps, but also with other electrical devices exist about, except to meet general requirements in Table 2, the wiring system, junction boxes, as well as switching and control devices placement, GB 16895.19 and the corresponding IEC standard requirements are related to the latest version:
1. Switch control means or socket
-. Zone 0 and 1 in the region can not be installed switches, control or power outlet Of reach (1.25m) than possible to install power outlets and switches outside a small pool area, allowing the district installed in a non-metallic cover sockets and switches, should be the origin of the power outlet and switch outside the zone 0, and should be above the ground 0.3m, in addition, protective measures should be taken to SELV or automatic power or electrical isolation -. In District 2, the installation switches, control device or an outlet, but the power supply circuit to meet SELV or automatic power or electrical isolation requirements 2 Junction box -.. in zone 0, you can not install the junction box -. In one area, only SELV junction box 3 Cabling System (1) General requirements -.. in Zone 0, Zone 1 and Zone cabling system 2 should be no accessible metal covering, untouchable metal coverings should be connected to an additional equipotential connections Region cabling system shall be limited to the. region that must be powered; -0 zone, a zone cabling system should be limited to only the area to supply power lines (2) Additional requirements fountain wiring cable for electrical equipment should be kept away from the edge of the area -0 pool. , in the pool of the line should be connected to the shortest path to the device, the cable should be laid in conduits in order to change the line; -1 regional cable laying should be suitable mechanical protection, wiring cable should be used 66IEC 245 or its equivalent performance cables, cable manufacturers should indicate that the permanent contact with water suitability.
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