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Fitting a security light- inductive load?

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Upforit | 18:39 Fri 08th Sep 2006 | Technology
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I was not sure where to post, so I have posted here and in home and garden. Hope the moderator(s) don't mind. My question is this. Some years ago I fitted a security light to the rear of my house. I took a spur off the main switch from my central heating. A qualified electrician (16th edition) told me that this was safe and acceptable, but I must use a six amp fused switch. I did this and all was ok. Recently the glass cover got broken (I posted for advice for replacing this, and have bought a complete new unit as they are only �7.99 each). Although I felt confident making the replacement, in the interests of safety I read the instructions that came with the new unit. There was a paragraph, which was not in the instructions of the old unit, which said it should not be connected to a circuit that has an inductive load. I understand that this means a circuit with a solenoid, motor or relay. While I am familiar with basic electrics, my knowledge does not extend to a gas central heating control circuit. While I imagine that there are such components in the circuit to activate valves and the motors can anybody (preferably a qualified electrician- my mate has moved away) tell me if a central heating control has an inductive load from the switch? The issue does not seem to be one of safety; merely that connection to this type of circuit may cause damage to electronic components in the PIR causing false triggering. Thanks in advance.
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The Inductive load in question would be a Lighting Dimmer Switch which will vary the voltage. P.I.R's dont like that.
Regards
Question Author
Thanks, badlad.biz but any circuit that has a solenoid, motor or relay has an inductive load. This is because these components use a 'peak' current that can be many times the normal running current. It is these peaks that are potentially damaging to the PIR components. What I need to know is should I worry about this by being spurred from a central heating control circuit? I know there are motors in this circuit and probably solenoids controlling gas flow, but are they significant with reference to replacing the old security light?
I also would find it hard to beleive that anything from the PIR could false trigger a Gas Solenoid on a boiler.
I would have thought the PIR would only control the load side of the switch.
Question Author
I understand what you are saying but the issue is not the PIR affecting the gas solenoid, but the gas solenoid/motor damaging the delicate electronic controls inside the PIR. When a motor or solenoid initiates, they draw a peak current for microseconds that can be vastly greater than a running system. This peak can damage the PIR�s electronic components. It is for this reason I would like to know if there could be an adverse effect on the PIR.
I just don't see a problem.
If one goes to extremes everything from Washing Machine and Refrigerator are Inductive. They are all connected to the same power supply, wether on the same circuit or at the busbar on the fuseboard.
I don't think any would sell if they were that unstable.
Question Author
Ok. badlad.biz. As I said earlier, I can see your point. My old security light did not seem to suffer any adverse effects, but perhaps the new one I have bought is technically improved and more sensitive. The advice in the installation instructions is not �DON�T USE IT NEAR ANYTHING ELSE!� It is that one should not connect it to a circuit that has an inductive load. Now, I can ignore this, or seek informed advice. You have advised me, and I am grateful for your input. However, not being trained to this level of electrical installation, I am merely asking for somebody who is to tell me simply there is nothing to be concerned about. The heating circuit will not adversely affect the delicate electronic components or find another circuit to take the spur from. Once again, thanks for your input.
I don't know about this problem but i want to suggest you to use video door phone for security reason. It is very reliable and easy to install.

http://videodoorphone...oor-phone-system.html

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