---
title: "W5100 hangs when i switch 220v loads"
url: "https://maker.wiznet.io/forum/10303"
markdown_url: "https://maker.wiznet.io/forum/10303/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "electrobrain"
created: "2014-06-14T07:20:47+09:00"
last_activity: "2017-05-04T08:33:12+09:00"
language: "en"
views: 455
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5100 hangs when i switch 220v loads

## Question

Asked by electrobrain on 2014-06-14 in Ethernet Chips.

Hi guys.
I’ve build a web server based on w5100 and mega32A.
I’ve observed all design recommendation that presented by wiznet.
Everything works well,But when I connect a Light Bulb running at 220V to relay output terminal It just turns ON once and then w5100 hangs and I will restart it manually. ![:frowning:](https://emoji.discourse-cdn.com/twitter/frowning.png?v=12)
I energizing the relay with a transistor and used a 1n4007 on relay coil.
Please help me.

## Replies

### Reply 1 by electrobrain, 2014-06-16

i noticed that if i away 220v wires from cat5 the situation is much better.and at this status it may hangs after 20 or 30 times relay turn ON/OFF
when i hit relay,the ping time from w5100 increased Significantly from 1ms to about 50ms or sometimes i’ve get ‘Request timed out’

However, I am sure that the problem is w5100. Because i defined 5 seconds timer for relay and after that times relay turn off properly.

### Reply 2 by peter, 2014-06-18

I think the cause may be from relay surge.
when relay turn on/off, Please check surge from relay.
If so, you have to concider circuit for protecting(or isolation) from relay contact.

### Reply 3 by electrobrain, 2014-06-19

> when relay turn on/off, Please check surge from relay.

how do i check it?

i test snubber (100R and 100nF),but it does not work.
also i test varistor in place of snubber but again without any success. ![:neutral_face:](https://emoji.discourse-cdn.com/twitter/neutral_face.png?v=12)

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Source: https://maker.wiznet.io/forum/10303