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I am going to wire a dedicated circuit for my 220v LG clone amp. I want to make a relay /outlet box similar to the one in notnyt's very informative thread. I tried using the search feature to find an answer with no success. I have the omron 30a relay( 4 terminals) as shown in the pictures below. My question is, how would this work since 220v has two hot wires? Any help would be appreciated. Thanks!

 

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Quote:
Originally Posted by petew  /t/1414677/wiring-relay-for-220v-pro-amp#post_22114717


You would need two of those relays, one for each hot leg.
Thanks man, I will order another.
 

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I had a similar question when wiring up my 240v pool pump to run off a digital timer. The switch I used said 120/240 and only had 4 terminals similar to your relay, called up my electrician and he just put the switch on one of the 2 hot legs going to the pump. The explanation being you need both hots connected to complete the circuit, if you lift one wire it breaks the circuit so no current can flow.

Most plans I've come across for remote amp turn on only use one relay, several AVS members have such setups. Having a switch on both legs is more expensive, the main benefit being that the amp is more isolated from power surges/lightning when off. I'm not an EE, but I don't know of any damage that can be caused by only switching one of the two hot legs for 220.


Based mine off this thread http://www.avsforum.com/t/1303723/automatically-powering-on-pro-amps-via-relay-guide-w-pics
 

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Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp#post_22157572


...if you lift one wire it breaks the circuit so no current can flow......

But that leaves you with energized equipment. If the equipment is off, it should not have juice anywhere. Current may not flow through the normal path but it sure as hell can flow through you.
 

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^^^ And where is the other side exposed for someone to touch it and make a conductive path?
 

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Quote:
Originally Posted by petew  /t/1414677/wiring-relay-for-220v-pro-amp#post_22158848


But that leaves you with energized equipment. If the equipment is off, it should not have juice anywhere. Current may not flow through the normal path but it sure as hell can flow through you.

The amp is no more dangerous than if it is plugged in and you turned off the power switch on the front of the unit. Yes, using only one breaker means that inside the amp chassis there is a live wire but how often are you working on a pro amp power supply with it plugged in? If you are taking the cover off an amp, electric motor, etc. and have it still plugged in I'm assuming you are fully aware of the risks you are taking and that you are a very competent electrician.


Its worth reiterating that you should unplug the relay, cut the breaker, whatever is necessary to remove power before working on any type of 120v/240v circuit.
 

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Discussion Starter #9
Thanks for the insight guys. I just about have it built with one relay. i am fully aware of the hazards of tinkering with electricity. The electrician that wired the outlet says he got zapped by 277v not long ago and it knocked him back quite a ways and he was huge.
 

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I modded my EP4000 to use a 12V trigger here .  Putting the Relay inside the amp is a far more elegant solution IMO, but I could be biased..


Not sure what the minimum clamping voltage is for your relay, hopefully you won't have too much voltage drop over your trigger wire and it will actuate proper. 

 

 
 

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Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22165063


The amp is no more dangerous than if it is plugged in and you turned off the power switch on the front of the unit. Yes, using only one breaker means that inside the amp chassis there is a live wire
If your device is plugged into the wall, and the outlet is on, then you have mains voltage to the ON/OFF switch or to the power relay inside the device.
Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22165063


but how often are you working on a pro amp power supply with it plugged in? If you are taking the cover off an amp, electric motor, etc. and have it still plugged in I'm assuming you are fully aware of the risks you are taking and that you are a very competent electrician.
The only time an amp should be energised and have the chassis opened to be worked on is if the amplifier itself is faulty - there is no need whatsoever for it to be energised to install a power relay.
Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22165063


Its worth reiterating that you should unplug the relay, cut the breaker, whatever is necessary to remove power before working on any type of 120v/240v circuit.
Not should, must.

Quote:
Originally Posted by keager  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22165098


i am fully aware of the hazards of tinkering with electricity. The electrician that wired the outlet says he got zapped by 277v not long ago and it knocked him back quite a ways and he was huge.
I work around high voltage every day, and getting zapped means you're not a competent electrician.

Quote:
Originally Posted by NicksHitachi  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22165152


Not sure what the minimum clamping voltage is for your relay, hopefully you won't have too much voltage drop over your trigger wire and it will actuate proper. 
If the relay draws so much current to activate the coil that it drops the receivers 12V trigger level, look for a high sensitivity relay, or use an auxiliary supply and transistor/FET to drive the relay from the trigger. Below is a eneric example and random google image.




Vcc is aux 12V supply

Data is 12V AVR trigger signal


A better how to for those interested.
 

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All good clarifications A9X, though I don't think I've ever met an electrician that hasn't been zapped at least once in his life. My buddy was replacing the service entrance line to my house, which floored me to see him standing on my roof holding live bare copper without getting a shock.
He explained how as long as your body doesn't complete a path to ground you're fine, then told me of one time when he was doing a similar job on a house he was holding the line and his elbow brushed the pole for the service entrance. Think I'll stick mainly to low voltage..
 

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Quote:
Originally Posted by A9X-308  /t/1414677/wiring-relay-for-220v-pro-amp#post_22165527


I work around high voltage every day

Many good points


A9,

Oftentimes, individuals/countries define "High Voltage" differently,... what do you mean by the term?


Thanks
 

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Quote:
Originally Posted by FOH  /t/1414677/wiring-relay-for-220v-pro-amp#post_22171538

Quote:
Originally Posted by A9X-308  /t/1414677/wiring-relay-for-220v-pro-amp#post_22165527


I work around high voltage every day

Many good points


A9,

Oftentimes, individuals/countries define "High Voltage" differently,... what do you mean by the term?


Thanks

1.21 Jigawatts!!
 

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Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22171272


He explained how as long as your body doesn't complete a path to ground you're fine, then told me of one time when he was doing a similar job on a house he was holding the line and his elbow brushed the pole for the service entrance.
Sorry, but I just see that as careless and depending upon where the conductive path was, say across the chest, he could have been killed.
Quote:
Originally Posted by FOH  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22171538


Many good points

A9,

Oftentimes, individuals/countries define "High Voltage" differently,... what do you mean by the term?

Thanks
AS3000 (1.4.98.c) defines it as exceeding 1000Vac/1500Vdc but I work on gear of up to 132kV. Normal mains of 240/415V is low voltage.
 

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Regardless of the technical/professional usage of the terms,...it's all perspective,.. ie, In the US, electricians, and many individuals that physically work with electricity, oftentimes refer to anything below 120vac as low voltage, anything above 480vac (perhaps up to 600v) as high voltage.


However, fire alarm techs, perhaps others working with LV controls etc, may refer to 120v as high voltage.


Also, your earlier point about getting shocked, you're right, they screwed up. Anytime one gets bit, if the person thinks about it, either they put themselves in a position they weren't entirely in control of, or they made a mistake. Either way, they're wrong*. Equally as serious is flash damage, and electrical shorts/explosions. Most lay people only think about shock/electrocution danger, many don't consider accidental flash/equipt failure etc. As you know, it happens and the energy released is phenomenal.


Thanks, your contributions are always appreciated.


*I guess there are times when an ungrounded piece of gear could shock the unsuspecting person,...to no fault of their own.



Thanks
 

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Quote:
Originally Posted by FOH  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22171943


Regardless of the technical/professional usage of the terms,...it's all perspective,.. ie, In the US, electricians, and many individuals that physically work with electricity, oftentimes refer to anything below 120vac as low voltage, anything above 480vac (perhaps up to 600v) as high voltage.

However, fire alarm techs, perhaps others working with LV controls etc, may refer to 120v as high voltage.
Extra low voltage here is
 

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Quote:
Originally Posted by A9X-308  /t/1414677/wiring-relay-for-220v-pro-amp#post_22172010


With regards to the last * point, nope, you test it before you touch it. Always assume it is energised, until proven de-energised.

I've spent a career in the field. Yes, you work everything as it's hot, you never ask anyone if "this is hot",.. you check yourself, or just proceed as it is. I worked w/13.8kv on down.


You misunderstood. What I was referring to stating;

"I guess there are times when an ungrounded piece of gear could shock the unsuspecting person,...to no fault of their own"


Say you touching/operating sometihng,... perhaps a power tool, and it becomes energized,..you unknowingly continue until encountering ground, then bam.


Thanks

All the best
 

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Quote:
Originally Posted by FOH  /t/1414677/wiring-relay-for-220v-pro-amp/0_100#post_22177805


You misunderstood. What I was referring to stating;
"I guess there are times when an ungrounded piece of gear could shock the unsuspecting person,...to no fault of their own"

Say you touching/operating sometihng,... perhaps a power tool, and it becomes energized,..you unknowingly continue until encountering ground, then bam.
In that case, you lock the breaker or breaker panel and mark it so that no one can operate or energise it inadvertently. Where I work we use cardboard Danger Tags of about A5 size that cannot be removed by anyone but the person whom installed it or is authorised by that person marked with date, name, phone number and reason for attaching. To ignore one is instant dismissal. For non industrial jobs, I have a small plastic lockable box that I can put the plug on a device in so it cannot be inserted into the power outlet and use a danger tag to indicate why. It then requires criminal stupidity on the part of someone to be able to energise a device I am working on.
 

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Quote:
Originally Posted by scorp133  /t/1414677/wiring-relay-for-220v-pro-amp/0_50#post_22157572


I had a similar question when wiring up my 240v pool pump to run off a digital timer. The switch I used said 120/240 and only had 4 terminals similar to your relay, called up my electrician and he just put the switch on one of the 2 hot legs going to the pump. The explanation being you need both hots connected to complete the circuit, if you lift one wire it breaks the circuit so no current can flow.

Most plans I've come across for remote amp turn on only use one relay, several AVS members have such setups. Having a switch on both legs is more expensive, the main benefit being that the amp is more isolated from power surges/lightning when off. I'm not an EE, but I don't know of any damage that can be caused by only switching one of the two hot legs for 220.

Based mine off this thread http://www.avsforum.com/t/1303723/automatically-powering-on-pro-amps-via-relay-guide-w-pics

each leg of that 220v is 120v to neutral (or earth ground). a relay in one leg will disable the pump (not allow current to flow), but there is 120v sitting on the other side. its best you break both legs.
 
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